Comparative floral structure and systematics in Chrysobalanaceae s.l. (Chrysobalanaceae, Dichapetalaceae, Euphroniaceae, Trigoniaceae; Malpighiales)

Botanical Journal of the Linnean Society

, 2002,

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, 321–381. With 104 figures

© 2002 The Linnean Society of London,

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, 321–381

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Blackwell Science, LtdOxford, UKBOJBotanical Journal of the Linnean Society0024-4074The Linnean Society of London, 2002140321381Original Article

FLORAL STRUCTURE and SYSTEMATICS IN OXALIDALESM. L. MATTHEWS and P. K. ENDRESS

*Corresponding author. E-mail: [email protected]

Comparative floral structure and systematics in Oxalidales (Oxalidaceae, Connaraceae, Brunelliaceae, Cephalotaceae, Cunoniaceae, Elaeocarpaceae, Tremandraceae)

MERRAN L. MATTHEWS* and PETER K. ENDRESS

Institute of Systematic Botany, University of Zurich, Zollikerstr. 107, CH-8008 Zurich, Switzerland

Received June 2002; accepted for publication August 2002

Floral morphology, anatomy and histology were studied in representatives of all families of current Oxalidales, whichwere recently constituted as a result of molecular systematic studies by other authors, and are composed of familiesof different positions in traditional classifications (Oxalidaceae, Connaraceae, Brunelliaceae, Cephalotaceae, Cunon-iaceae, Elaeocarpaceae, Tremandraceae). Two of the three pairs of sister (or nested) families that come out inmolecular analyses are highly supported by floral structure: Oxalidaceae/Connaraceae and Elaeocarpaceae/Trem-andraceae, whereas Cephalotaceae/Cunoniaceae are not especially similar at the level of Oxalidales. Oxalidaceaeand Connaraceae share petals that are postgenitally united into a basal tube (although they are imbricate in both)but free at the insertion zone, stamens that are congenitally united at the base, uniseriate glandular hairs on the sta-men filaments, and ovules that are hemianatropous to almost orthotropous. The sharing of a special type of sieve-tube plastids and of trimorphic heterostyly, studied by other authors, should also be mentioned. With Brunelliaceae,the two families share an androgynophore and nectaries at the base of the stamens in alternisepalous sectors. Elae-ocarpaceae and Tremandraceae share buzz-pollinated flowers and a syndrome of features functionally connectedwith it. In addition, petals are larger than sepals in advanced bud, they are valvate, involute and enwrap part of theadjacent stamens, they have three vascular traces. Lignified hairs are common on the anthers and are found in theovary locules and on the ovules (not lignified) of representatives of both families. Ovules have a chalazal appendage,and the inner integument is much thicker than the outer. © 2002 The Linnean Society of London,

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, 2002,

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, 321–381.

ADDITIONAL KEYWORDS:

androecium – core eudicots – eurosids I – gynoecium – perianth – rosids.

INTRODUCTION

The current molecular revolution in angiosperm sys-tematics has resulted in some major regroupings oflarger taxa. In core eudicots a number of newly con-ceived orders have appeared (APG, 1998). One of theseorders is Oxalidales in eurosids I. According to APG(1998), Oxalidales are composed of six families: Oxal-idaceae, Connaraceae, Cephalotaceae, Cunoniaceae,Elaeocarpaceae and Tremandraceae. More recentchanges include the addition of Brunelliaceae(included in Cunoniaceae in APG, 1998) (Savolainen

et al

., 2000), but the subtraction of Tremandraceae,

which appear to be nested in Elaeocarpaceae inmolecular analyses (Savolainen

et al

., 2000; Soltis

et al

., 2000). This clade of current Oxalidales beganto take shape in the earliest

rbcL

analysis ofangiosperms (Chase

et al

., 1993; Morgan & Soltis,1993), comprising Oxalidaceae, Cephalotaceae, Trem-andraceae and Cunoniaceae; and all these familieswere placed in the same clade in the combined non-DNA and

rbcL

analysis by Nandi, Chase & Endress(1998) (but also including Strasburgeriaceae andParacryphiaceae). In addition, Anisophylleaceae maybe related to Oxalidales (Matthews, Endress &Schönenberger, 2001; Schönenberger

et al

., 2001)based on morphological (including palaeobotanical)grounds, although they appear in Cucurbitales in

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molecular (

rbcL

) studies (Schwarzbach & Ricklefs,2000; Wagstaff & Dawson, 2000). In addition, phylo-genetic resolution in basal clades of core eudicots isstill poor. It may therefore be expected that in future,after more detailed analyses, the topology will changebetween and also within current orders.

In traditional classifications, such as those byCronquist (1981), Takhtajan (1997), and Thorne(2000), the families of current Oxalidales (and includ-ing Anisophylleaceae) were in several different orders,not all of which are especially closely related, andsome even appeared in different subclasses. InCronquist’s (1981) classification, a number of familieswere in subclass Rosidae, but in different orders:Geraniales (Oxalidaceae), Rosales (Anisophylleaceae,Brunelliaceae, Connaraceae, Cunoniaceae and Ceph-alotaceae), and Polygalales (Tremandraceae). Elaeo-carpaceae, in contrast, were in subclass Dilleniidae(order Malvales). In Takhtajan’s (1997) classification,although placed in the same subclasses, the number oforders for these families was greatly expanded. Thosein subclass Rosidae were: Cunoniales (Brunelliaceae,Cunoniaceae), Cephalotales (Cephalotaceae), Con-narales (Connaraceae), Oxalidales (Oxalidaceae),Vochysiales (Tremandraceae) and Anisophylleales(Anisophylleaceae), while Elaeocarpaceae, althoughremaining in Dilleniidae, were placed in their ownorder, Elaeocarpales. In Thorne’s (2000) classificationthe families were equally distributed in Rosidae andDilleniidae. Those in Rosidae included Cunoniales(Brunelliaceae, Cunoniaceae, Cephalotaceae), andRosales (Anisophylleaceae), while the remainder wereplaced in Dilleniidae: Violales (Elaeocarpaceae),Rutales (Connaraceae), and Geraniales (Oxalidaceae,Tremandraceae). A placement of Elaeocarpaceae out-side of Malvales had previously been suspected(Dahlgren, 1988). However, the most surprising newcoalition is Tremandraceae (former Rosidae, except forThorne, 2000) seemingly nested in Elaeocarpaceae(former Dilleniidae). Thus, the newly conceived Oxal-idales (APG, 1998) are composed of formerly very dif-ferent components.

To date, studies of the floral structure of these fam-ilies are unevenly proportioned or essentially lacking.For example, in Cephalotaceae, Connaraceae andElaeocarpaceae detailed studies on floral morphologyand anatomy, based on living flowers or liquid-fixedflowers, have previously not been carried out. Thismay be partly due to the lignified hairs and oftenheavily tanniferous tissues which makes these flowersdifficult to section with a microtome when embeddedin paraffin or paraplast. Floral developmental studiesare also scarce and cover only very few single taxa inOxalidaceae (Payer, 1857; Frank, 1876; Moncur, 1988;Richards & Barrett, 1992), Connaraceae (Tucker &Douglas, 1994), Cunoniaceae (Dickison, 1989; Moody

& Hufford, 2000), Elaeocarpaceae (van Heel, 1966),and Tremandraceae (Payer, 1857); they are in somecases fragmentary, or were not carried out using newtechniques.

It therefore seemed timely, in the light of the conflictbetween the traditional classifications and of theappearance of a new classification based on molecularstudies (APG, 1998; Savolainen

et al

., 2000; Soltis

et al

., 2000), to conduct a comparative study on thefloral structure of these families. In this investigationwe focus on all seven families of current Oxalidales:Oxalidaceae, Connaraceae, Brunelliaceae, Cephalota-ceae, Cunoniaceae, Elaeocarpaceae and Treman-draceae. We also include Anisophylleaceae in thediscussion because of their potential close relation-ship with Oxalidales (see Matthews

et al

., 2001;Schönenberger

et al

., 2001).In each family(if not mono-generic) species of two or more genera were studied inorder to find potential synapomorphies. Results fromthe literature were considered as much as possible.

An additional general problem is that detailed com-parative studies on flowers of groups of rosids (or coreeudicots) are scarce, so that detailed morphologicalcomparisons over a larger segment (let alone all fam-ilies) of rosids are not yet possible. Thus it is unavoid-able in this situation that character evaluationsremain tentative. However, this study should be acontribution to a more comprehensive understandingof the morphology (including anatomy and histology)of this vast group of angiosperms.

MATERIAL AND METHODS

The following taxa were examined:

Oxalidaceae

Oxalis ortgiesii

Regel; P. K. Endress 4346, cult.Botanical Garden of the University of Zurich (BGZ);buds and open flowers.

Biophytum dendroides

DC.; P. K. Endress 7591, cult.BGZ; buds and open flowers; M. L. Matthews MM008,cult. BGZ; buds and open flowers.

Averrhoa carambola

L.; P. K. Endress 4158, cult.Botanical Garden Lae, Papua New Guinea; buds andopen flowers.

Connaraceae

Cnestis ferruginea

DC.; P. K. Endress 99–11, IvoryCoast; buds and open flowers.

Connarus conchocarpus

F. Muell.; P. K. Endress9074, cult. CSIRO, Atherton, northern Queensland,Australia; buds and open flowers.

Brunelliaceae

Brunellia standleyana

Cuatrec.; J. Gomez-Laurito,s.n., June 2001, Costa Rica; buds and open flowers.

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Cephalotaceae

Cephalotus follicularis

Labill.; P. K. Endress 7847,cult. BGZ, buds and open flowers; P. K. Endress 7878,cult. BGZ; open flowers; M. L. Matthews MM012, cult.BGZ; buds and open flowers.

Cunoniaceae

Acsmithia davidsonii

(F. Muell.) Hoogland; A. K.Irvine 1212, northern Queensland, Australia; buds; B.Jago, s.n., northern Queensland, Australia; postan-thetic flowers.

Ceratopetalum gummiferum

Sm.; P. K. Endress6344, cult. Old Botanic Garden, Brisbane, Australia;buds and open flowers.

Geissois pruinosa

Brongn. et Gris; P. K. Endress6005, New Caledonia; young buds.

Geissois biagiana

F. Muell.; P. K. Endress 9211,northern Queensland, Australia; buds and openflowers.

Schizomeria whitei

Mattf., P. K. Endress 4209,northern Queensland, Australia; buds and openflowers.

Elaeocarpaceae

Aristotelia chilensis

Stuntz; P. K. Endress 946, cult.old BGZ; buds and open flowers.

Elaeocarpus

cf.

subvillosus

Arn.; P. K. Endress 00–14a, cult. Fazenda St. Eliza, Campinas, S.P., Brazil;buds and open flowers.

Crinodendron patagua

Molina; P. K. Endress 2649,cult. old BGZ; buds and open flowers.

Sloanea macbrydei

F. Muell.; P. K. Endress 9024,northern Queensland, Australia; buds and open flow-ers.

Vallea stipularis

L.f.; J. Schönenberger and M. vonBalthazar JS495, Bolivia; buds and open flowers.

Tremandraceae

Platytheca galioides

Steetz; A. George ASG17595 &ASG17598, West Australia; buds and open flowers.

Tetratheca ciliata

Lindl. A. Bohte, s. n. 2001, cult.Melbourne University, Australia; buds and openflowers.

Tetratheca thymifolia

Sm.; P. K. Endress 6144,southern Queensland, Australia; buds and open flow-ers; A. Bohte, s.n., 2001, cult. Maranoa Gardens, Mel-bourne, Australia; buds and open flowers.

Flowers and floral buds, fixed in FAA and stored in70% ethanol, were used for light (LM) and scanning(SEM) microscopy. For serial microtome sectionsspecimens were embedded in Kulzer’s Technovit (2-hydroethyl methacrylate), as described in Igersheim(1993) and Igersheim & Cichocki (1996), and sectionedwith a Microm HM 335 rotary microtome and conven-tional microtome knife D. Transverse and longitudinal

sections were made. The mostly 5

m

m thick sectionswere stained with ruthenium red and toluidine blue(Weber & Igersheim, 1994). All sections were mountedin Histomount. For SEM studies, specimens weredehydrated in ethanol and acetone, critical-pointdried, and sputter coated with gold. All vouchers andpermanent slides of the microtome sections are depos-ited at the Institute of Systematic Botany of the Uni-versity of Zurich (Z), Switzerland.

Abbreviations used in figures are sepal (s); petal (p);anther (a); dehiscence pore or slit of theca (d); carpel(c); style (st); placenta (pl); ovule (ov); outer integu-ment (o); inner integument (i); obturator (ob); nectary(n).

RESULTS

Floral structure is described for selected genera of allfamilies of the order Oxalidales as currently circum-scribed. The descriptions are based on advanced floralbuds, in which male meiosis has already taken place.This stage was preferred over anthetic flowers, as theperianth organs are still in an upright position, thusentire flowers could be studied in transverse section.The gynoecium at anthesis was also studied whenmaterial was available. The flowers are generallydescribed from the top, downward (i.e. distally toproximally).

O

XALIDACEAE

Oxalis ortgiesii

Morphology.

Flowers are bisexual, 5-merous (isomer-ous) and obdiplostemonous (Fig. 1). The slightlypointed sepals are congenitally united at their base(Fig 1J,K); they have quincuncial aestivation. Thethick petal claws of the salverform flowers arepostgenitally united except at their narrow base(Figs 1H,I,57A); petal aestivation is contort. Stamensare congenitally united (for one third of their length)in a tube (Figs 1I,79). Episepalous stamens are longerand more or less straight in bud, epipetalous stamenshave recurved anthers (Fig. 79). Anthers are small,dorsifixed, mainly x-shaped, introrse and versatile(Fig. 34). The connective is broad, and a protrusionmay be broad and incised, narrow and long, short, orabsent; protrusions are more pronounced on episepa-lous stamens. Thecae dehisce by a longitudinal slit. Ashort, non-vascularized filament-like outgrowth ofuncertain nature is present on the dorsal side of thefree region of each episepalous filament (Fig. 1G). Thecarpels are epipetalous, they are free in the upperstyle, with a superior ovary; they are of angiospermytype 3 (Fig. 1A–H,A

¢

–G

¢

) (for terminology, see Endress& Igersheim, 2000). The ovary flanks are expanded

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Figure 1.

Oxalis ortgiesii

(Oxalidaceae). Floral bud, TS series. A, directly below stigmas. B, level of episepalous anthersand free carpels; ventral slits postgenitally fused (dotted lines). C, symplicate zone of style. D, upper symplicate zone ofovary, central gap present between united carpels. E, upper synascidiate zone at level of placentae. F, level of epipetalousanthers. G, level of filament outgrowth on episepalous stamens. H, level of postgenitally united petals (dotted lines). I,level of stamen tube. J, level of congenitally united sepals and androgynophore; nectaries (shaded) in epipetalous sectors.K, directly above floral base. L,M, floral base. A

¢

–G

¢

, higher magnification of gynoecium for A–G. Scale bars

=

1 mm in A–M; 400

m

m in A

¢-

G

¢

.

A

E

B C D

F G

JH I

K L M

F´ G´DĆ´BÁ´ E´


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2002,

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into broad longitudinal ribs, while the dorsal ovaryregion is narrow. The ovary is synascidiate for twothirds of its length, and up to the upper third of theplacenta (Fig. 1E–H,E

¢

–G

¢

). Stigmas are decurrent,slightly expanded, and have multicellular smoothprotuberances (Fig. 84); secretory at anthesis (in

O. corniculata

, with unicellular papillae on the protu-berances, Shibaike, Ishiguir & Kawano, 1995). Theventral slit extends up to the stigma, and is postgen-itally fused in the style except for the upper plicatezone (Fig. 1B,C,B

¢

,C

¢

). A stylar canal extends up to theupper symplicate region. The pollen tube transmittingtissue (PTTT) is present as a massive column in eachcarpel. In the plicate region it is c. nine to 12 cell lay-ers in diameter; in the upper symplicate region it isreduced to two cell layers on either side of the ventralslit (it does not encompass the stylar canal); directlyabove the ovary, it is reduced to a single cell layerlining the ventral slits and the gap in the centre of thegynoecium. A compitum seems to be present in thisregion. In the synascidiate zone, a vertical strip ofPTTT extends to the funicles along the ventral surfaceof the locule. One to three pendant ovules are presentper carpel (Fig. 65A). Placentation of the upper twoalternating ovules is lateral, but median in the thirdovule (if present) (in other

Oxalis

species ovule num-ber per carpel may be as high as 24, but it is low inmost species; Salter, 1944). Ovules are bitegmic, andanatropous; they have a small chalazal appendage(Fig. 72). When the embryo sac is mature, the nucellushas disappeared, thus the ovules are probably tenui-nucellar, as described for

Oxalis corniculata

(Herr &Dowd, 1968) and for

O. valdiviensis

(Bouman, 1974).The nucellus and inner integument are elevated on astalk within the outer integument, a feature, whichmay relate to the expulsion mechanism of the innerportion of the seed from its outer testa (Fig. 72) (forthis mechanism in

Oxalis

, see Overbeck, 1923). Theupwardly directed, irregularly shaped micropyle isformed by both integuments, as in

O. corniculata

(Herr& Dowd, 1968) and in

O. valdiviensis

(Bouman, 1974).Both integuments are lobed. In the lower ovule(s) theouter integument is extended into a funnel-like expan-sion, which surrounds the chalazal appendage of theupper ovule (Fig. 72). The outer integument is four tosix cell layers thick, the inner three to four. Anendothelial layer is present in the inner integument.Androecium and gynoecium are congenitally fusedinto a short androgynophore (Fig. 1J,K). At this level,nectaries are present below the epipetalous stamens(Fig. 1J). A floral cup is not formed.

Anatomy.

Sepals have three to five main (and mayhave one to three additional smaller) vascular bun-dles, and three vascular traces in the floral base(Fig. 1). Petals have one trace that divides into six to

seven bundles in the distal direction. Stamens haveone vascular bundle. The dorsal carpel bundle is thinand not fully differentiated, extending from the ovaryto the plicate zone of the style (it is in the plane wherethe fruit later dehisces). Two main lateral bundlesextend up to the free stylar region. Two additional lat-eral bundles are present in the symplicate zone of theovary below the ribs and unite with the main lateralbundles below the placenta. Directly above the pla-centa the main lateral bundles of adjacent carpelsunite into synlaterals. Additional synlaterals (closer tocarpel margins) end above the placenta in the ovary.Downwards, at the level of the placenta these addi-tional synlaterals divide into lateral bundles, whichserve the ovules of adjacent carpels. Below the pla-centa they form ventral bundles, which unite in astar-shaped central bundle complex together with thesynlaterals, which form the points of the star. Thestamen traces join this central complex. In the floralbase, lateral traces of adjacent sepals unite into syn-laterals. Petal traces join the sepal synlaterals of thesame radius, thus the peripheral bundle system con-sists of five major bundle complexes and the mediansepal traces. These together join the central bundlecomplex.

Histology.

Stomata (not raised) are present on thenectary; stomata are raised on the upper dorsal side ofthe sepals, anther connective and style. Unicellularlignified tanniferous hairs with warty ornamentation(Fig. 82) are present on all floral organs and eveninside the ovary locule. Sauer (1933) mentions similarhairs on carpels in

Oxalis corniculata

. Multicellular,uniseriate (slightly moniliform), glandular hairs arepresent on the stamen filament including the out-growth on the episepalous stamen filament (Fig. 82),style (Fig. 84), and ovary. Short unicellular glandularhairs are present at the base of the ventral petalsurface. Sepal and carpel mesophyll is conspicuouslylarge-celled (Sauer, 1933; also for carpels of

O. corniculata

) and cells of the sepal and carpel epider-mis have a thickened outer wall. Tanniferous cells arepresent in the connective protrusion. Cells withoxalate crystals are present in the sepals, petals,anther connectives, nectaries, and ovary base; druseswere not found.


Morphology.

Flowers are bisexual, 5-merous (isomer-ous), and obdiplostemonous (Fig. 2). Sepals are elon-gate, with a broad base, a pointed apex, and thinmargins (two cell layers thick); they have quincuncialaestivation; the overlapping flanks seem to be partlypostgenitally coherent. Petals are clawed; they arepostgenitally united for most of the claw, except forthe narrow base (Figs 2B–G,57B); they have contort

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Figure 2.


(Oxalidaceae). Floral bud, TS series. A, level of episepalous anthers. B, level of epipetalousanthers and free carpels. C, level of postgenitally united petals (dotted lines) and symplicate zone of style. D, symplicatezone of ovary above level of placentae. E, symplicate zone at level of placentae. F, synascidiate zone at level of placentae.G, ovary below level of placentae. H, end of short staminal tube. I, end of androgynophore; ovary locules present as slits.J, nectaries (shaded) in epipetalous sectors. K–N, floral base. D

¢

–G

¢

, higher magnification of gynoecium for D–G. Scalebars

=

1 mm in A–N; 400

m

m in D

¢

–G

¢

.

A B C

G´

FE

D

H

J K L

NM

I

F´D´ E´

G


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2002,

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aestivation. Stamens are more or less straight (epise-palous anthers sometimes slightly recurved). Episepa-lous stamens have longer and thicker filaments thanepipetalous ones. Anthers are dorsifixed, x-shaped,introrse and versatile, with a broad connective and asmall protrusion (Fig. 35). Thecae dehisce by a longi-tudinal slit. The carpels are epipetalous, they are freefor the majority of the style, with a superior ovary;they are of angiospermy type 3 (Fig. 2B–I,D

¢

–G

¢

). Thethin-walled ovary is synascidiate for three quarters ofits length, extending up to the upper fifth of theplacenta (Fig. 2F–I,F

¢

,G

¢

). Stigmas are two-lobed, uni-cellular papillate and decurrent in the recurved freestylar region, secretory at anthesis. The ventral slitextends to the stigma, and is postgenitally fusedexcept for the upper plicate zone. Directly above theovary, narrow stylar canals are present in individualcarpels. The ventral slit is lined by a single layer ofPTTT, which seems to form a compitum in the sympli-cate zone where a gap is present in centre of the gyno-ecium (Fig. 2C–E,D

¢

,E

¢

). Six to eight lateral ovules percarpel alternate in two vertical lines (Fig. 65B). Theyare bitegmic, tenuinucellar (according to Boesewinkel,1985; species not indicated and without figure), andhemianatropous. The micropyle is conspicuously zig-zag-shaped and forms a longitudinal slit. It could notbe ascertained whether or not the integuments arelobed. A secretion is present in the part of the micro-pyle formed by the inner integument. Both integu-ments are three cell layers thick. An endothelium isnot differentiated. In the centre of the basal region ofthe ovary large intercellular spaces are present; herethe ovary locules form radial slits (Fig. 2I). Andro-ecium and gynoecium are congenitally fused into ashort androgynophore (Fig. 2I,J). At this level, necta-ries are present below the epipetalous stamens(Fig. 2I,J). Sepal margins remain free below the floralbase for some distance (Fig. 2K,L). A floral cup is notformed.

Anatomy.

Sepals have five to seven well-developedmain (and three to five additional smaller) vascularbundles (Fig. 2). Within individual sepals, smallerbundles fuse with adjacent larger bundles (particu-larly in the lateral flanks). Five to seven vasculartraces are present in the floral base. Petals have asingle trace that divides into five bundles in a distaldirection. Stamens have a single vascular bundle. Inthe carpels, the dorsal bundle extends up to the sym-plicate region of the style where it is thin and undif-ferentiated (it is in the plane where the fruit laterdehisces). Two main lateral bundles extend up to thefree stylar region. An additional two (to three) lateralbundles are present in the symplicate region of thestyle, basipetally increasing in number in the ovary(four to six bundles present). Directly above the pla-

centa in the ovary, the two main lateral bundles ofadjacent carpels unite into synlaterals. The bundlesthat serve the ovules branch from a second set ofsynlaterals (closer to the carpel margins). Below theplacenta, this second set of synlaterals unites into acentral bundle complex. In total, three bundle seriesare present: five inner secondary carpel synlaterals, amiddle series of ten carpel bundles (five dorsal bundlesand five primary synlaterals), and ten outer stamenbundles. The middle and inner series fuse to form acentral ring of 15 carpel bundles. The area of the dor-sal carpel bundles fuses with the epipetalous stamenbundles, and the area of the carpel synlaterals fuseswith the episepalous stamen bundles. At the floralbase, lateral sepal bundles unite and join the centralbundle complex. Petal traces join the central bundlecomplex separately or after fusion with the mediansepal trace. The remaining sepal traces fuse directlywith the central vascular complex.

Histology.

Stomata are present on both sides of thesepals, the anther connective and protrusion, and thenectary (rare). Those on the anthers and some onthe dorsal side of the sepal are raised. Long twistedunicellular, lignified, tanniferous hairs arise frommulticellular protuberances on the upper dorsal sideof the sepals. Shorter, lignified (non-twisted) hairs arepresent on stamen filaments and on the gynoecium.Multicellular, uniseriate, glandular hairs are presenton the petals (Fig. 76) and gynoecium. The epidermisis tanniferous in all organs, including the inner epi-dermis of the ovary and the ovule periphery. Cells withoxalate crystals are present in sepals, stamen fila-ments, and ovary; druses were not found.

Averrhoa carambola

Morphology.

Flowers are bisexual, 5-merous (isomer-ous), and obdiplostemonous (Fig. 3). In older buds,petals are slightly longer than sepals and thus bothare protective. Sepals have a broad base and a pointedor rounded apex, they are congenitally united for avery short distance (Fig. 3I–K), and have a quincun-cial aestivation. Petals have a narrow base, a broad,rounded blade, and contort aestivation; they areslightly postgenitally connected in the narrow part bytheir hooked lateral flanks (in TS) (Figs 3G,H,74). Thestamens are congenitally united into a short tube(Figs 3H–J,80). The (fertile) episepalous stamens arelonger than the (antherless) epipetalous staminodesand are more or less straight in bud (Fig. 80). Theiranthers are dorsifixed, x-shaped, introrse and versa-tile, with a broad connective and a small protrusion(Fig. 36). Thecae dehisce by a longitudinal slit.Staminodes have a short, narrow, filamentousincurved upper region (Figs 3F,80), and a broad, flatlower part, which is nectariferous on both sides, also

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Figure 3.

Averrhoa carambola

(Oxalidaceae). Floral bud, TS series. A, level of free carpels. B, symplicate zone of style;ventral slits postgenitally fused (dotted lines). C, level of episepalous anthers and upper synascidiate zone of gynoecium.D, ovary above level of placentae. E, at level of placentae. F, level of tips of epipetalous staminodes. G, level of postgenitallyconnected petals (dotted lines) and nectariferous region (shaded) of epipetalous staminodes. H, end of staminal tube. I,level of staminal tube. J, level of short androgynophore. K–M, floral base. C

¢

–G

¢, higher magnification of gynoecium for C–G. Scale bars = 1 mm in A–M; 400 mm in C¢–G¢.

A B C D

E F G H

I J K L M

E´DĆ´ G´F´

FLORAL STRUCTURE AND SYSTEMATICS IN OXALIDALES 329

© 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 2002, 140, 321–381

in the basal tube (Figs 3G–J,80). The carpels are epi-petalous, they are free in the upper style, with a supe-rior, completely synascidiate, thick-walled ovary; theyare of angiospermy type 3 (Fig. 3A–H,C–¢G¢). The dor-sal region of each carpel is expanded into a pro-nounced longitudinal rib, which reinforces the starshaped outline. Stigmas are broad, decurrent andhave multicellular, smooth protruberances (Fig. 85).The ventral slit and stylar canal extend up to thestigma. The ventral slit is postgenitally fused belowthe stigmatic zone (Fig. 3B). The PTTT is one to twocell layers thick in the ventral slit and part of thecanal. A compitum seems to be present in the uppersymplicate zone. In the synascidiate zone PTTT con-tinues in the remnants of the ventral slit and part ofthe locular wall. Placentation is ‘lateral’ (although inthe synascidiate zone), each locule containing fouralternating ovules (Fig. 65C). They are bitegmic,crassinucellar (see Boesewinkel, 1985), and anatro-pous. The zig-zag micropyle, formed by both integu-ments, appears as a longitudinal slit; it is directedupwards, towards the placenta (Fig. 66). The outerintegument is lobed, the inner unlobed. The outerintegument is four cell layers thick, the inner four tofive. An endothelium is not clearly differentiated.Androecium and gynoecium are congenitally fusedinto a short androgynophore (Fig. 3J). A floral cup isnot formed.

Anatomy. Sepals have five main (and three to fiveadditional smaller) vascular bundles in the free region(Fig. 3). In the congenitally united region, the two lat-eral-most secondary bundles of adjacent sepals oftenunite into synlaterals, and at the floral base ten maintraces are present in the calyx. Smaller sepal bundlesoften persist below the floral base, where they fusewith larger neighbouring bundles. Petals have onetrace that divides into 10–12 bundles in a distal direc-tion. Stamens have one vascular bundle. Carpels havea (relatively weak) dorsal bundle and two main lateralbundles that extend up to the stigma. An additionalsix to seven lateral bundles extend up to the synascid-iate zone of the lower style. These bundles unite witheach other and the main lateral bundles in the ovary.Directly above the placenta, the main lateral bundlesof adjacent carpels unite into synlaterals. Ovules aresupplied by additional lateral bundles (closer to thecarpel margin), sometimes united into synlaterals(Dave, Patel & Rupera, 1975). The synlaterals andadditional lateral bundles unite below the placentainto a central bundle complex. The dorsal bundles jointhis central complex at the floral base and togetherthey form a five-pointed star, with the dorsal bundlesat the points. In the floral base, the bundles in theregion of the lateral carpel bundles (of adjacent car-pels) fuse with the episepalous stamen traces. The epi-

petalous stamen traces join the petal traces andsynlateral sepal traces. The bundles in the region ofthe dorsal carpel bundles fuse with these complexes.The median sepal traces fuse directly with the centralbundle complex.

Histology. Stomata (not raised) are present on thedorsal side of the sepals and on the nectary, and raisedstomata are concentrated on the dorsal side of theanther connective and protrusion, and on the style,below the stigma. Multicellular uniseriate (monili-form) glandular hairs are present on petals (see alsoChin & Phoon, 1982) (Fig. 77), stamen filaments andgynoecium. In addition, unicellular lignified, tannifer-ous hairs are present on the gynoecium, and multicel-lular (occasionally biseriate) hairs are present on thepetals. Sepal mesophyll is conspicuously large-celled.The ovary is large-celled in the centre, but the ovarywalls are conspicuously small-celled and relativelymeristematic. This seems to be a precondition for thedevelopment of the large, thick-walled fruit (asopposed to the small, thin-walled fruits of Oxalis andBiophytum). Tanniferous tissue surrounds the vascu-lar bundle in the anther connective, and is present inthe epidermis and hypodermis of the style and theperiphery of the ovule. Cells with oxalate crystals arepresent in the sepals and anther connectives andovary; druses were not found.

CONNARACEAE

Cnestis ferruginea

Morphology. Flowers are bisexual, 5-merous, com-monly isomerous, and obdiplostemonous (Fig. 4).Sepals have a broad base and a pointed apex. They areinvolute-valvate; there is postgenital cohesion byhairs (Fig. 20). Five almost circular petals havecochlear (in four flowers) or quincuncial (in one flower)aestivation (Schellenberg, 1938, mentions quincuncialpetal aestivation for Connaraceae in general). Theyare occasionally slightly incised (one eighth of length)into c. three to eight small lobes (Fig. 57D,D¢). The sta-mens are congenitally united into a very short tube(Fig. 4G,H). Anthers are slightly recurved in bud,strongly so in the open flower such that they appearinverted (Fig. 38). Anthers are dorsifixed, x-shaped,introrse (but flipping backwards at anthesis so as tobecome seemingly extrorse), and versatile, with a thinconnective and without a protrusion (Figs 37,38).Each theca is basally extended into a sterile tip. The-cae dehisce by a longitudinal slit not extending to thetip (Fig. 38). Episepalous filaments are thicker andlonger, and epipetalous ones broader. Five free car-pels are epipetalous, one to two additional episepal-ous carpels are also occasionally present (Fig.

330 M. L. MATTHEWS and P. K. ENDRESS


4B–H,D¢–F¢); they have superior ovaries, and are ofangiospermy type 3. The ovary is ascidiate for athird of its length, extending up to the lower third ofthe placenta (Fig. 4F–H,D¢–F¢). In the ascidiate zonean external furrow, which is an extension of the ven-tral slit, extends to the carpel base (Figs 4F–H,F¢,60)(for other Connaraceae see Leinfellner, 1 970;Dickison, 1971). Stigmas are decurrent, pointed andslightly reflexed; they are unicellular papillate, andsecretory at anthesis. The ventral slit extends upto the stigma; the stylar canal ends below thestigma. PTTT lines the stylar canal and inner part ofthe ventral slit, and in the ovary continues along theventral slit to the placenta. Each locule contains twocollateral ovules at its base. Ovules are bitegmic,crassinucellar and hemianatropous. They are imma-ture at anthesis. At this stage, the micropyle isformed by the inner integument as an irregular slit,

and is directed towards the locule ceiling. It couldnot be ascertained whether the integuments arelobed at maturity. The outer integument is two tothree cell layers thick, the inner three. An endothe-lium is not differentiated. The remnant floral apexbetween the free carpels is slightly convex. Smallnectary lobes protrude outwards between the sta-men filaments (Fig. 4F–H). The stamen tube is con-genitally fused with the dorsal part of the freecarpels for a very short distance before it fuses withpetals and sepals (comparable to an androgyno-phore) (Fig. 4G,H). Sepal margins remain slightlyfree below the floral base (Fig. 4I). A floral cup is notformed.

Anatomy. Sepals have three main (and five to sixadditional smaller) vascular bundles and three vas-cular traces in the floral base (Fig. 4). The smaller

Figure 4. Cnestis ferruginea (Connaraceae). Floral bud, TS series. A, level of episepalous anthers. B, level of epipetalousanthers and free carpels. C, upper plicate zone of ovaries. D, level of postgenitally connected petals (dotted lines). E, levelof placenta in plicate zone. F, level of placenta in ascidiate zone, note external ventral furrow. G,H, level of nectaries(shaded). I,J, floral base. D¢–F¢, higher magnification of gynoecium for D–F. Scale bars = 1 mm in A–J; 400 mm in D¢–F¢.

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sepal bundles join the main ones, and lateral bundlesof adjacent sepals unite into synlaterals. Petals have asingle trace and four to seven bundles in the blade.Stamens have a single vascular bundle. Carpels havea median dorsal bundle and two main lateral bundlesthat extend up to the upper style and end in a band ofxylem elements (joined over the middle). In the ovarysome smaller secondary bundles appear, forming anetwork with the main bundles. A large ventral carpelbundle is present in the ascidiate zone, which suppliesthe two ovules (Fig. 60). At the floral base, the ventraland lateral carpel bundles unite forming a central ringcomplex. The dorsal carpel bundles of epipetalous car-pels join the epipetalous stamen bundles of the sameradii, and these complexes join the median sepalbundles. The episepalous stamen bundle joins thesynlateral sepal trace of the same radius, and thiscomplex bundle joins the central ring of carpel bun-dles. Vascular bundles of carpels not in an epipetalousposition join the nearest main bundle complexes.Together these complexes form a central bundlecomplex.

Histology. The hypodermis of the dorsal side of thesepals contains two to three layers of cells withthickened (mucilaginous) inner tangential walls; suchcells also continue downwards on the pedicel. Raisedstomata are present on the dorsal side of the sepals.Stomata on the nectary are not raised. Petals arepapillate on the ventral surface, near the petal base;these cells seem to be slightly meristematic. Two typesof (tanniferous) hairs are present: (1) non-glandular,unicellular, lignified, on the dorsal surface of thesepals, petals, lower style, ovary and on the convexfloral apex, and (2) glandular, with a multicellular,uniseriate stalk and a multicellular head on the dorsalsepal surface (Fig. 20). Tanniferous cells are scatteredin all floral organs, especially concentrated in the sta-men filaments. Cells with oxalate crystals are presentin all floral organs; cells with druses are present inthe petals (the ventral surface appearing ‘bumpy’due to the presence of cells with large druses in thehypodermis).

Connarus conchocarpus

Morphology. Flowers are bisexual, 5-merous (gyno-ecium 1-merous), and haplostemonous (Fig. 5). Inolder buds, petals are longer than sepals, and thus arethe protective organs (Fig. 5A). Sepals have a broadbase and a pointed apex; margins may be two cell lay-ered; they are not postgenitally coherent; aestivationis quincuncial (in four flowers), or cochlear (in oneflower). Petals are elongate with a narrow base(Fig. 57E). At the tip, aestivation is cochlear, valvatebelow; they are postgenitally united in the valvate

area by their thin, slightly hooked lateral flanks(Figs 5B,75). Only episepalous stamens are present,and sometimes also one or two epipetalous staminodes(Fig. 81). They are congenitally united into a shorttube (Figs 5E,81). Stamens are upright in bud.Anthers are dorsifixed, sagittate, introrse, and versa-tile, with a broad connective and a small protrusion(Fig. 39). Thecae dehisce by a longitudinal slit. Thesingle carpel has a superior ovary; it is of angiospermytype 3 (Fig. 5D). The ovary is ascidiate for a fifth of itslength, extending up to the base of the placenta(Fig. 5D). The stigma is large, broad, convoluted anddecurrent (Fig. 86), secretory at anthesis. The ventralslit extends up to the stigma and is present as anexternal ventral furrow in the ascidiate zone(Figs 5D,E,61) (Leinfellner, 1970; for Connarus gibbo-sus). The stylar canal ends immediately below thestigma. PTTT lines the stylar canal and the inner partof the ventral slit as a single cell layer and extends tothe upper part of the ovary locule near the micropylesalong either side of the ventral slit. Each locule con-tains two collateral ovules (Fig. 61). In bud andanthetic flowers, one ovule may be aborted (see alsoSchellenberg, 1938). Ovules are bitegmic, crassinucel-lar (see also Mauritzon, 1939; for C. ellipticus), andalmost orthotropous (only curved at the base)(Mauritzon, 1939). The apically flattened, irregularlyslit-like micropyle is formed by the inner integumentand is directed and appressed towards the locule ceil-ing. Both integuments are lobed. The outer integu-ment is five cell layers thick, the inner four. Anendothelium is differentiated on the inner integu-ment. There are five nectariferous areas in the epipe-talous sectors of the ring of the congenitally unitedstamen bases (Figs 5E,81); they are distinguishableby the presence of stomata, but not by especially cyto-plasm-rich tissue. An androgynophore is not formed.Sepal margins remain partially free below the floralbase (Fig. 5G,H). A floral cup is not formed.

Anatomy. Sepals have three main (and two to threeadditional smaller) vascular bundles and three vascu-lar traces (Fig. 5). Petals have a single trace and threeto five bundles in the blade. Stamens have a singlevascular bundle. Additional smaller bundles arepresent in the epipetalous sectors (below the necta-ries) in the floral base. The carpel has a dorsal bundleand two main lateral bundles that extend up to theupper style. Numerous secondary lateral bundles forma ring in the ovary wall between the dorsal and mainlateral bundles, and form a network with them. At thelevel of the placenta, a large ventral bundle is presentthat supplies the two ovules (Fig. 61). Below the pla-centa, this bundle unites with the ring of main andsecondary bundles in the ovary wall. Below the ovarylocule, the carpel bundles unite into a ring, the last to



Figure 5. Connarus conchocarpus (Connaraceae). A–C, E–I, floral bud, TS series. A, level of episepalous anthers and stigma.B, level of postgenital connection between petals (dotted lines). C, level of ovary. D, gynoecium of floral bud, in ascidiatezone at level of placenta. Note external ventral furrow and ventral vascular bundle between ovules. E, level of androgy-nophore; nectaries (shaded) in epipetalous sectors. F, near floral base. G–I, floral base. Scale bars = 1 mm in A–C, E–I;400 mm in D.

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join is the dorsal bundle. The lateral bundles of adja-cent sepals unite into synlaterals. Carpel bundles fusewith the epipetalous stamen and petal bundles of thesame radius, and these complexes fuse with the sepalsynlaterals. Other carpel bundles fuse with the epise-palous stamen traces and the synlateral bundles of thesepals.

Histology. The ventral sepal epidermis contains cellswith thickened (mucilaginous) inner tangential walls(Fig. 26). Large mucilage-filled cavities (yellow stain-ing) are present (term used by Dickison, 1971) in thesepal mesophyll, petals, and gynoecium. Stomata (notraised) are present on the dorsal surface of the sepalsand on the nectary. Unicellular lignified, tanniferoushairs are present on the dorsal sepal surface and car-pel. Glandular hairs with uniseriate, slightly monili-form stalk and a multicellular head are present onpetals (Fig. 78), stamens (Fig. 83) and style (Fig. 86).Tanniferous cells are present in all floral organs, espe-cially concentrated in the epidermis. Cells withoxalate crystals are present in sepals, carpels and nec-taries; cells with druses are present in the anther con-nective. Petal margins in the lower area (including thepostgenitally united region) are not tanniferous butseem to be meristematic or secretory (Fig. 75).

BRUNELLIACEAE

Brunellia standleyana

Morphology. Flowers are bisexual, and female (seeCuatrecasas, 1970) (4-)5-merous, commonly isomer-ous, and diplostemonous (Fig. 6) (stamen numbersomewhat variable, sometimes slightly increased inother species; Engler, 1930b; Cuatrecasas, 1970). Theflowers of the collection studied are functionallyfemale, with relatively well developed, but sterile sta-mens (Figs 40,58). Sepals are thick, with a broad baseand a pointed apex. They are valvate; there is post-genital cohesion by hairs (Fig. 21). Petals are absent.In bud, the stamens of both whorls are upright orslightly incurved. Anthers are dorsifixed, x-shaped,slightly introrse, and versatile, with a broad connec-tive and a small protrusion (Fig. 40). Thecae dehisceby a longitudinal slit. Filaments are longer thananthers in bud, episepalous filaments broader, thicker,and longer than alternisepalous ones. Carpels arealternisepalous, united only at their base, with asuperior ovary; they are of angiospermy type 3(Fig. 6A–H). The ovary is ascidiate for three quartersof its length, extending up to near the top of theplacenta (Fig. 6E–H). There is a very short synascid-iate zone (Fig. 6G,H). In bud, the tapering styles of



individual carpels are strongly incurved (Figs 6A,58),and recurved at anthesis. Stigmas are decurrent downthe entire ventral side of the style, unicellular papil-late, and secretory at anthesis. The ventral slitextends up to the stigma. In the ascidiate zone, it isrestricted to an external furrow (Figs 6E,F,62). Thestylar canal ends below the stigma. PTTT lines thestylar canal and ventral slit as a single dark-stainingcell layer and extends into the ovary locule on eitherside of the ventral slit, and as a median strip inthe ascidiate zone along the placenta/funicle. Twocollateral, pendant ovules are present in each locule(Figs 6D–H,62). Ovules are bitegmic, crassinucellar,anatropous, and have an obturator; they do not fill thelocule. The micropyle is formed by both integuments,

it is directed upward, and is shaped like a longitudinalslit; the distal-most part of the lobed outer integumentis expanded and surrounds the obturator (Fig. 70).Both integuments are lobed. The outer integument istwo cell layers thick, the inner four. An endothelium isnot differentiated. A very short androgynophore isformed that includes only the episepalous stamens(Fig. 6I); it exhibits nectariferous zones in the alter-nisepalous sectors (Fig. 6G–K). The sepal marginsremain free for some distance below the floral base(Fig. 6J–L). A floral cup is not formed.

Anatomy. Sepals have three main (and two to threeadditional smaller) vascular bundles and three vascu-lar traces in the floral base (Fig. 6). Stamens have a

Figure 6. Brunellia standleyana (Brunelliaceae). Female floral bud, TS series. A, level of incurved styles. B,C, level of sterileepisepalous anthers. D, level of sterile alternisepalous anthers and placenta in plicate zone of ovaries. E, ascidiate zone ofovaries at placenta, note external ventral furrow and ventral vascular bundle between the ovules. F, ovaries below levelof placenta. G,H, synascidiate zone; nectaries (shaded) in alternisepalous sectors. I, partial androgynophore (only episepa-lous stamens fused with gynoecium). J–L, floral base. Scale bar = 1 mm.

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single vascular bundle. Carpels have a median dorsalbundle and two main lateral bundles, which extend tothe stigma. A basipetally increasing number (up to c.16) of secondary lateral bundles form a network withthe main bundles in the lower style and ovary. In theplacenta, a median ventral bundle is present (notdescribed by Eyde, 1970) that divides and supplies thetwo ovules (Fig. 62). Below the placenta it forms acomplex with the lateral bundles, and in the synascid-iate zone these four complexes form a central ring.Some remaining secondary laterals of individual car-pels join the bundle complex of the same sector. Fur-ther secondary laterals fuse with the episepalousstamen traces or the dorsal carpel bundles, which thenjoin the central bundle complex of the same sector. Thenectaries are served by a number of small bundles,which branch from episepalous and alternisepalousstrands. At the floral base, secondary sepal traces fusewith the neighbouring median sepal trace, which jointhe episepalous stamen traces and the central vascu-lar ring of the same sector. The alternisepalous sta-men traces fuse with the laterals of adjacent sepals,and this complex joins with the central ring ofbundles.

Histology. Stomata (not raised) are present on thedorsal side of the sepals and on the nectary surfaces.Short papillae are present on the dorsal sepal surface.Unicellular lignified, tanniferous hairs are present onthe sepals (on the dorsal side some have a bulbousbase), lower style and ovary wall. Unicellular thin-walled cells are present at the base of the stamens.Tanniferous tissue is lacking (apart from the hairsmentioned). Cells containing oxalate crystals ordruses are present in the sepals, surrounding the vas-cular bundle of the stamens, in the stigma, style, funi-cle and ovary wall.

CEPHALOTACEAE

Cephalotus follicularis

Morphology. Flowers are bisexual, 6-merous (isomer-ous), and obdiplostemonous (Fig. 7). They are pro-nouncedly protandrous. Sepals have a broad base;they are thick, particularly at the pointed tip where aprominent ventral ‘hood’ is present; aestivation is val-vate at this ‘hooded’ region, below revolute-valvate insome sectors, imbricate in others; there is postgenitalcohesion by cuticular dentation. Petals are absent.Stamens are incurved in bud, the episepalous onesmore so and are therefore covered by the alter-nisepalous ones; the ventral epidermis of the fila-ments is wrinkled by this incurving. Episepalousstamen filaments are longer, thicker and broader thanalternisepalous ones. Anthers are dorsifixed, x-

shaped, introrse, and versatile, with a thin connectiveand a prominent protrusion (Fig. 41). Thecae dehisceby a longitudinal slit. The free, alternisepalous carpelshave a tapering apex and a superior ovary; they are ofangiospermy type 4 (Fig. 7B–H,E¢–H¢). They are short,erect, and hairless in early anthesis, and later becomelonger, recurved, and hairy. The thin-walled ovary(only four to five cell layers thick) is plicate. Stigmasare decurrent, unicellular papillate, and secretory atanthesis. The ventral slit is postgenitally fused; it doesnot extend up to the stigmatic region. A stylar canal isabsent. PTTT lines the ventral slit as a single celllayer (restricted to the inner part of the ventral slit inthe mid- to lower style) and extends into the ovary loc-ule on either side of the ventral slit down to theplacenta/funicle. PTTT is involved in the production ofthe secretion, which fills the locule. Placentation isbasal-lateral (Fig. 7H,H¢). The funicle of the singleovule passes from the placenta on the ventral side ofthe carpel, underneath the micropyle along the base ofthe locule to the dorsal side (Fig. 7G,H,G¢,H¢). Theovule is bitegmic, seemingly weakly crassinucellar,anatropous; it is directed downwards and it fills thelocule. The circular micropyle is formed by the innerintegument; the funicle obstructing the closure of theouter integument. Both integuments are unlobed.Secretion, produced by the exposed flanks of the innerintegument, fills the micropyle and the space betweenthe integuments. The outer integument is two to threecell layers thick, the inner three to five. An endothe-lium is not differentiated (Schweiger, 1909 mentioneda dark staining inner epidermis of the inner integu-ment, which probably prompted Cronquist, 1981 toassume the presence of an endothelium). The remain-ing floral apex is a convex mound surrounded by thecarpels (Fig. 7G,H). The nectary forms a broad ringaround the gynoecium with distinctive protuberances(Vogel, 1998) emerging from its surface (Fig. 7C–I).Sepals and stamens are inserted on a floral cup(Figs 7F–I,17).

Anatomy. Sepals have three main (and four to sixadditional smaller) vascular bundles (Fig. 7). Second-ary sepal bundles may fuse with neighbouring mainbundles in the short congenitally united region abovethe floral cup. Stamens have a single vascular bundle.Carpels have a dorsal bundle that extends to thestigma and two shorter main lateral bundles, whichextend to the mid-stylar region, occasionally an addi-tional secondary lateral. Although the single ovule isbasal-lateral, it is supplied by a median bundle which,together with the lateral bundles, forms a complexbundle shortly below the placenta. In the floral cup,alternisepalous stamen bundles join the synlateraltraces of adjacent sepals of the same radius, and epise-palous stamen bundles join the median sepal bundle



Figure 7. Cephalotus follicularus (Cephalotaceae). Floral bud, TS series. A, hooded zone of sepals and bulbous connectiveprotrusion of alternisepalous anthers. B, level of alternisepalous anthers and free carpels. C, level of episepalous anthersand nectary protruberances (shaded). D, upper region of ovaries, ventral slits postgenitally fused (dotted lines). E, end ofcongenitally united sepals. F, end of floral cup. G, ovaries directly above placenta, note funicle positioned abaxial to ovule;nectaries (shaded) confluent. H, level of placenta. I–K, floral base. E¢–H¢, higher magnification of gynoecium for E–H. Scalebars = 1 mm in A–K; 400 mm in E¢–H¢.

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of the same radius. This results in 12 bundle com-plexes in the floral cup. The dorsal carpel bundles jointhe alternisepalous, floral cup bundle complexes. Theventral-lateral complex divides into two branches; thebranch complex of adjacent carpels join the episepal-ous floral cup bundle complexes of the same sector,together forming a ring of bundle complexes.

Histology. On the dorsal side of the sepals, raised andunraised stomata are present. Stomata are also raisedon distinctive protuberances on the nectary; eachprotuberance bears a stoma with eight to ten subsid-iary cells. The hooded region of the sepals comprises alarge-celled tissue with large intercellular spaces;intercellular spaces are also present in the ovularraphe and outer integument. The anther connective isdistinctive with large, convex cells (Fig. 41). Endress& Stumpf (1991) suggest these structures may act as‘pseudonectaries’, their surface glistening. Unicellularlignified, tanniferous hairs are present on the dorsalside of the sepals and on the convex floral basebetween the carpels. Tanniferous cells are present inthe anther connective and filament, the epidermis ofthe ventral slit in the style, funicle, the inner epider-mis of the inner integument, the nectary epidermis,and the tissue underlying the nectary (here containingstarch). Cells with oxalate druses and crystals areabsent.

CUNONIACEAE

Acsmithia davidsonii

Morphology. Flowers are bisexual, 4(-5)-merous and(ob)diplostemonous (a distinction between obdiploste-monous and diplostemonous is problematic becausethe gynoecium is only 2(- 3) merous) (Fig. 8). Thepointed tips of the thin sepals are incurved inside thebud; aestivation is involute-valvate at the tip, revo-lute-valvate below; the sepals are congenitally unitedat their base (Fig. 8E–I); in the free part, there is post-genital cohesion by cuticular and cellular dentation.Petals are absent. Stamens are not tightly packedin bud; they are more or less straight. Anthers aredorsifixed, x-shaped, slightly introrse, and versatile,with a narrow connective and without a protrusion(Fig. 42). Thecae dehisce by a longitudinal slit. Episep-alous stamen filaments are slightly broader, thicker,and longer than alternisepalous ones. If two carpelsare present they seem not exactly opposite each other,instead one has a more episepalous, the other a morealternisepalous position; they are free, but congeni-tally united at the base, with a superior ovary; theyare incurved in bud (Figs 8A–H,59); the angiospermytype is uncertain because only pre- and postantheticgynoecia were available. The ovary is ascidiate for half

of its length (including a very short synascidiate part)(Fig. 8F,G), extending up to the lower fifth of the pla-centa. Stigmas are capitate with elongate, unicellularpapillae. The ventral slit and a stylar canal extend upto the stigma. They are lined with a single cell layerof PTTT, but in the ovary PTTT encompasses morecell layers. In the ascidiate zone the ventral slit isrestricted to an external furrow (Fig. 8F). Four (to six)collateral ovules are arranged along two verticallines (Fig. 65D). Ovules are bitegmic, crassinucellar,and anatropous; the micropyle is directed upwards.Anthetic ovules were not available, thus the shape ofthe micropyle and lobation of integuments could notbe ascertained. In preanthetic ovules the outer integ-ument is two to three cell layers thick, the inner three.An endothelium is not differentiated. A nectary discis irregularly continuous or discontinous (dependingupon available space) between the adaxial side of thestamen filaments and the gynoecium, and protrudesbetween the stamen filaments (Fig. 8F–I). A floral cupis not formed.

Anatomy. Sepals have mostly three main (and up totwo additional smaller) bundles in the free region(Fig. 8). Lateral bundles of adjacent sepals remainununited in the congenitally fused region, thus(mainly) 12 sepal traces are present in the floral base.Stamens have a single vascular bundle. Carpels havea dorsal bundle and two main lateral bundles thatextend to the stigma. In the ovary four to six addi-tional secondary lateral bundles are present, whichunite with each other and join the main lateral bun-dles. The main lateral bundles supply the ovules in theplicate zone. In the ascidiate zone, the main lateralbundles unite into a ventral bundle complex, whichtogether forms a central bundle complex with theremaining secondary lateral bundles in the synascid-iate zone. In the floral base, the dorsal carpel tracesfuse with this complex, lower down the stamen tracesand then the sepal traces. The entire vascular complexforms a stele in the pedicel.

Histology. Stomata are present on the dorsal side ofthe sepals (slightly raised) and on the nectary lobes(not raised). Unicellular lignified, tanniferous hairsare present on dorsal side of sepals, ovary and lowerstyle. Tanniferous cells are present in the stamens,stigma, style, placenta, ovule periphery and thenectary lobes (nectary epidermis not distinct in bud,tanniferous in postanthetic flower). Cells with oxalatedruses and crystals are absent.

Geissois biagiana

Morphology. Flowers are bisexual (Fig. 9). The (fourto) five sepals have a broad base and pointed apex;



they are revolute-valvate and are congenitally unitedfor a short distance at their base (Fig. 9F–I). In thefree part there is postgenital cohesion by hairs(Fig. 22). Petals are absent. The 17–21 stamens (16–26, according to Schimanski & Rozefelds, 2002) areincurved in bud. Episepalous stamens are in triple,quadruple or quintuple positions and their filamentsvary in length; the median ones are longer than thelateral ones; alternisepalous ones are in single posi-tion. Episepalous stamen filaments are narrower,thinner and longer than alternisepalous ones. Anthersare dorsifixed, x-shaped, introrse and versatile, with athin connective and without a protrusion (Fig. 43).Thecae dehisce by a longitudinal slit. The two carpelsare united in the superior ovary; they are ofangiospermy type 3 (Fig. 9A–H). The ovary is synas-cidiate for two thirds of its length, extending to the

lower third of the placenta (Fig. 9F–H). The stigma iscapitate, slightly decurrent, unicellular papillate, andsecretory at anthesis. The ventral slit and stylar canalextend up to the stigma. The ventral slit is postgeni-tally fused in the style but is visible as an external fur-row (in anthetic flowers). In the synascidiate zone, aninternal furrow is present in the locule as a continua-tion of the ventral slit (Fig. 9F–H). The stylar canaland ovary locules are filled by secretion. PTTT linesthe ventral slit and stylar canal as a single cell layer(rich in cytoplasm but not darkly stained). A shortcompitum seems to be present in the symplicate zoneof the ovary. In the ovary locules the PTTT extends tothe ovules on either side of the ventral slit. The c. 19–20 collateral ovules per locule (5–10, according toSchimanski & Rozefelds, 2002) are arranged in twovertical lines (Fig. 65E). Ovules are bitegmic, crassi-

Figure 8. Acsmithia davidsonii (Cunoniaceae). Floral bud, TS series. A, level of episepalous anthers and free carpels. B,level of alternisepalous anthers; ventral slits postgenitally fused (dotted lines). C, upper plicate zone of ovary above levelof placentae. D, plicate zone at level of placentae. E, end of congenitally united sepals and plicate zone below level ofplacentae. F, ascidiate zone below level of placentae, note external ventral furrows; end of nectaries (shaded). G,H;synascidiate zone. I, level of short androgynophore. J–L, floral base. Scale bar = 1 mm.

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nucellar, and anatropous; the raphe forms a rib. Themicropyle is formed by the inner or by both integu-ments and faces downwards, towards the placenta. Asit is covered by massive secretion, its shape is difficultto ascertain. Both integuments are unlobed. The outerintegument is two cell layers thick, the inner three.An endothelium is not differentiated. A continuousnectary disc surrounds the gynoecium and protrudes

between some stamen filaments; these protrusions aremore extended vertically than horizontally so that thenectary has the shape of a cog-wheel (Figs 9F–H,63). Afloral cup is not formed.

Anatomy. Sepals have three main (and four addi-tional, smaller) vascular bundles (Fig. 9). Secondarysepal bundles unite with the main bundles in the con-

Figure 9. Geissois biagiana (Cunoniaceae). Floral bud, TS series. A, level of free styles (styles reflexed, therefore appearingtwice). B, level of episepalous anthers and free styles. C, symplicate zone of ovary at level above placentae. D, symplicatezone at level of placentae. E, level of alternisepalous anthers. F,G, synascidate zone at level of nectary disc (shaded) andend of congenitally united zone of sepals. H, level of inferior ovaries. I–K, floral base. Scale bar = 1 mm.

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genitally united zone and at the floral base; lateralbundles of adjacent sepals remain ununited, thus c. 15main bundles are present at the floral base. Stamenshave a single vascular bundle. Carpels have a dorsalbundle that extends up to the stigma and two slightlyshorter main lateral bundles. A basipetally increasingnumber of secondary (up to 20) lateral bundles arepresent in the lower style and ovary, which form a net-work with the main bundles. In the lower symplicatezone, the main lateral bundles of adjacent carpelsunite into synlaterals. In the synascidiate zone, thesynlaterals unite into a large central vascular com-plex. The ovules are served by the main lateral bun-dles in the upper symplicate zone, by the synlateralsin the lower symplicate zone and by the central vas-cular complex in the synascidiate zone. In the floralbase, the main and secondary carpel bundles joinneighbouring stamen bundles (such complexes some-times uniting) and then join the nearest sepal trace.Lateral traces of adjacent sepals unite into synlater-als, and form a complex with neighbouring stamentraces, as do the median sepal traces. All bundle com-plexes of the peripheral organs join the central bundlecomplex. In the nectary disc, numerous small, prima-rily phloic strands are present, which join neighbour-ing stamen and carpel bundles.

Histology. Tanniferous cells with thickened (mucilag-inous) inner tangential walls are present in the dorsalhypodermis and ventral epidermis of the sepals(Figs 22,27) and in the ventral epidermis of the upperstyle, below the stigma; such cells also continue down-ward on the pedicel. Mucilage cells are present in thesepal mesophyll. Stomata are present on the dorsalside of the sepals (some raised) and on the nectary.Unicellular lignified, tanniferous hairs are present onthe sepals, gynoecium and nectary. Tanniferous cellsare abundant in all floral parts including the ovuleperiphery and the inner epidermis of the inner integ-ument. Cells with oxalate crystals are present in theovary locules; cells with druses are present in thesepals, stamens, and carpels.

Geissois pruinosa

Androecium development. Flowers have (three to)four sepals, no petals, 12–14 stamens and two carpels.In advanced buds stamens are in a single series(Figs 30,31). In each episepalous sector there are com-monly three stamens, and in each alternisepaloussector there are one to two stamens. The medianepisepalous stamen (or stamen pair) is initiated first.Subsequent initiation takes place progressively,towards the sepal margins. The alternisepalous one totwo stamens are initiated last (see also Dickison,1989).

Schizomeria whitei

Morphology. Flowers are bisexual (4-)5–6-merous,and (ob)diplostemonous (a distinction betweenobdiplostemonous and diplostemonous is problematicbecause the gynoecium is only 2(-3)-merous) (Fig. 10).Sepals have a broad base and pointed apex, they arethick and hooded; aestivation is valvate; there is post-genital cohesion mainly by cellular dentation (somealso by cuticular dentation and by hairs). Petals havea narrow base (Figs 10D,57F,F¢) and wide blade thathalfway surrounds the epipetalous stamens. They donot overlap. They are incised for one third of theirlength to form three main pointed lobes; an additionalshort incision may be present in each lateral lobe, suchthat the tips are divided into two small lobes. Aesti-vation is open. Stamens are incurved in bud. Anthersare sagittate, dorsifixed, introrse and versatile, with athin connective and a protrusion (Fig. 44). Thecaedehisce by a longitudinal slit. Episepalous filamentsare slightly broader, thicker, and longer than epipeta-lous ones. In bud, the anther and filament are almostof equal length. The two (to three) carpels are taper-ing at the apex and are united up to mid length ofthe style, with a semi-inferior ovary; they are ofangiospermy type 3 (Fig. 10A–F,E¢). The ovary issynascidiate for half of its length, extending up todirectly above the placenta (Fig. 10E,F,E¢). The stig-mas are punctiform and unicellular-papillate, secre-tion seems to be absent at anthesis. The ventral slit ispresent up to the stigma. A stylar canal is either notdistinct or is present for some distance and filled withsecretion. In the symplicate zone, a gap is present inthe centre of the gynoecium. PTTT lines the ventralslit with a single cell layer, and also lines the lowerpart of the central gap, where a compitum seems to bepresent. PTTT extends to the placenta on either side ofthe ventral slit. Placentation is lateral, and two pairsof collateral ovules are present per locule (Fig. 65F).Ovules are bitegmic, crassinucellar, and hemianatro-pous (also in S. serrata, Mauritzon, 1939). The zig-zagmicropyle forms a longitudinal slit (Fig. 67) and isdirected upwards, towards the ventral slit. Both integ-uments are unlobed. The outer integument is threecell layers thick, the inner four to six. An endotheliumis not differentiated. A nectary disc surrounds thegynoecium and protrudes between the stamen fila-ments (Fig. 10C,D). A short floral cup is formed by theperianth and androecium, including the nectary(Fig. 10E), however, the sepal margins are still visibleon the outer surface of the floral cup (Fig. 10F,G).

Anatomy. Sepals have three main (and one to twoadditional, smaller) vascular bundles and three vas-cular traces in the floral base (Fig. 10). Petals have onevascular trace that divides into three to five bundlesserving the petal lobes. Stamens have a single vascu-



Figure 10. Schizomeria whitei (Cunoniaceae). Floral bud, TS series. A,B, level of anthers and free styles. C,D, symplicatezone of style and level of nectary (shaded). E, level of floral cup and synascidate zone. F, level of inferior ovary. G,H, floralbase. E¢, higher magnification of gynoecium for E. Scale bars = 1 mm in A–H; 500 mm in E¢.

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lar bundle. Carpels have a dorsal bundle that extendsto the stigma and two shorter main lateral bundles. Inthe symplicate zone above the ovary, two additionallateral bundles (near the margins) are present, origi-nating (from below) from the main lateral bundles.

Numerous secondary carpel bundles form a networkwith the main bundles in the thick ovary wall. In theplacenta, in the synascidiate zone, the lateral bundlesof adjacent carpels unite into synlaterals, these bun-dles supply the ovules and downwards form a central



bundle complex. In the floral base, secondary carpelbundles unite with each other and fuse with stamenbundles. Episepalous stamen complexes fuse with themedian sepal bundles. Epipetalous stamen complexesfuse with petal bundles of the same radius, and withthe lateral bundles of adjacent sepals. Thus theperipheral bundle system consists of (eight to) 10–12vascular complexes. Below the ovary locules theperipheral complexes fuse with the central bundlecomplex. The nectary has a network of many smallphloem strands, which join neighbouring larger vas-cular bundles, primarily the stamen traces.

Histology. Stomata are present on the dorsal side ofthe sepals (slightly raised) and on the nectary lobes(sunken). The hooded region of the sepals containslarge intercellular spaces. Unicellular lignified, tan-

niferous hairs are present on the dorsal side and edgesof the sepals, and on the ovary. Tanniferous cells areabundant in all floral parts including the inner epider-mis of the inner integument. Cells with oxalate crys-tals were not found; cells with druses are present in allorgans except for the ovules and nectary.

ELAEOCARPACEAE

Aristotelia chilensis

Morphology. Flowers are bisexual. The perianthwhorls are 5-merous (Fig. 11). Sepals have a broadbase and a pointed apex; they are slightly quincuncial,and almost valvate; there is postgenital cohesion byhairs (Fig. 23). Petals have a narrow base and a broadblade with an undulating apical margin (Fig. 57G).

Figure 11. Aristotelia chilensis (Elaeocarpaceae). Floral bud, TS series. A, level of anther tips and free styles. B, level ofanthers and symplicate zone of style. C, symplicate zone of ovary above level of placentae. D, end of nectary disc (shaded).E,F, level of floral cup and synascidiate zone at level of placentae. G,H, level of inferior ovary. I,J, floral base. Scalebar = 1 mm.

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Aestivation is either cochlear (in three flowers) orquincuncial (in two flowers). There are five episepal-ous stamens and ten slightly shorter epipetalous onesin double positions. They appear as five groups ofthree stamens: an episepalous stamen and two epipe-talous ones (Fig. 11B–D). Anthers are longer than fil-aments. They are basifixed, elongate, x-shaped, andslightly introrse with a narrow connective and withouta protrusion. Dehiscence is by a short longitudinal slitat the end of each theca. The two to three carpelsare congenitally united up to the upper style, with ac. 1/3 inferior ovary; they are of angiospermy type 3(Fig. 11A–H). The ovary is synascidiate for half of itslength, extending up to the upper third of the shortplacenta, which is at mid-height of the ovary(Fig. 11E–H). Stigmas are decurrent on all sides of thetapering carpels, but slightly more on the ventral side;they are unicellular papillate and secretory atanthesis. The ventral slit extends up to the stigma.Individual stylar canals are present throughout thesyncarpous part of the style. In the symplicate zone ofthe placenta the ventral slits are gaping. PTTT linesthe ventral slits as a single conspicuous cell layer andextends to the placentae on either side of the ventralslits. A compitum seems to be present in the uppersymplicate zone. Placentation is lateral and each loc-ule contains two (to three) alternating ovules, orien-tated at 45∞ to more or less horizontal. Ovules arebitegmic, crassinucellar, anatropous, and a chalazalappendage is present (Fig. 99). The irregularly slit-like micropyle is formed by the inner integument(occasionally by both); the micropyle of the upperovule is directed sidewards and downwards, and thelower ovule is directed sidewards and upwards. Theouter integument is unlobed, the inner is lobed(Fig. 99). The outer integument is five to six cell layersthick, the inner seven to ten. An endothelium is notdifferentiated. A nectary disc surrounds the gynoe-cium and episepalous stamens, and protrudesbetween the two epipetalous stamens of each pair(Fig. 11D–G). An extremely short floral cup is formed(Figs 11E–G,19). However, sepal margins remain freefor a very short distance below the floral base(Fig. 11G).

Anatomy. Sepals have three main (and one to two sec-ondary) vascular bundles, and three vascular traces inthe floral base (Fig. 11). Some secondary bundles unitewith the main bundles above and at the level of the flo-ral cup. Petals have a single trace, which divides intonine to 12 bundles in the blade. Stamens have a singlevascular bundle. In the carpel, a thin undifferentiateddorsal bundle may be present in the lower style andupper ovary. It is differentiated into a bundle in thelower ovary. Two lateral bundles extend up to the styleand end in a band of xylem elements (joined over the

dorsal side) below the stigma. In the ovary wall, c. 12–14 secondary vascular bundles are present, whichform a network with the main bundles. Above the pla-centa the main lateral bundles of adjacent carpelsunite into synlaterals, which supply the ovules. Inthe synascidiate zone at the base of the placenta thesynlaterals unite into a central vascular complex. Atthe level of the floral cup, petal bundles fuse with thelateral traces of adjacent sepals. This complex is thenjoined by a trace from each adjacent epipetalous sta-men pair. Secondary carpel bundles may fuse to neigh-bouring stamen bundles. In the floral base, the dorsalcarpel bundle joins the neighbouring stamen com-plex(es), and the episepalous stamen traces join themedian sepal traces. The central carpel bundle com-plex is surrounded by a peripheral series of ten bundlecomplexes. Altogether they form a central bundle com-plex. In the nectary disc, numerous small (primarily)phloic strands are present, which join the nearest sta-men traces or secondary carpel traces.

Histology. Stomata are present on the dorsal sepalsurface (those near the tip raised), and on the nectary(not raised). Endothecium, with mainly inner cellwalls thickened, is continuous over the dorsal and ven-tral side of the anther; it ceases at the stomium and isalso lacking at the anther base. Unicellular lignifiedhairs are present in the sepal distal area and margins,on the petals, filaments and anthers (broad based onthe anthers) (in sepals also unlignified ones). Tannif-erous cells are scattered in the epidermis (and hypo-dermis) of the sepals, in the petals, anther connective,filament, lower style, ovary, and nectary. Cells withoxalate crystals and/or druses are present on the ven-tral side of the sepals, in the petals, stamens, andcarpels.

Crinodendron patagua

Morphology. Flowers are bisexual. The perianthwhorls are 5-merous (Fig. 12). In older buds, petals aremuch longer than sepals, thus the petals are the pro-tective organs (Figs 12A–J,87). As the flowers are pen-dant, the perianth base is bulged upwards towards thepedicel (Fig. 12P). Sepals are thin and congenitallyunited, forming a short collar with five tips at the baseof the corolla (Figs 12K–P,87); in advanced buds thecalyx tears into two parts, always in alternisepaloussectors (Fig. 12L–O). The induplicately valvate petalsare large, elongate with a narrow base, and twiceincised (one sixth of length) to form three pointedlobes: a central, and two shorter, involute lateral lobes(Fig. 57H). At the base of each petal a pronounced ven-tral, non-vascularized ridge is present (Fig. 12D–N),which results in two tubular accesses to the nectar(Fig. 12K–N). Petals are basally coherent by hairs.There are five episepalous stamens, and ten shorter



Figure 12. Crinodendron patagua (Elaeocarpaceae). Floral bud, TS series. A, level of symplicate style, ventral slits notpresent. B, level of anther tips and style, ventral slits present. C, level of style, ventral slits postgenitally fused (dottedlines). D, level of stamen filaments. E, upper symplicate zone of ovary. F,G, synascidiate zone at level of placentae. H,ovary below level of placentae. I, ovary below level of ovules; nectary portions (shaded) present. J, level of cog-wheel-shapednectary disc (shaded). K, below ovary locules; sepal tips present. L,M, level of congenitally united sepals and petal fusionto androgynophore. N–P, level of upwardly bulging (because flower pendant) perianth and floral base (sepals and petalsbulging below floral base in P). Q, floral base. A¢–G¢, higher magnification of gynoecium for A–G. Scale bars = 2 mm in A–Q; 400 mm in A¢; 500 mm in B¢-D¢; 1 mm in E¢–G¢.

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epipetalous ones in double positions (occasionally 11with a triple position). Anthers of pairs of epipetalousstamens are wrapped in individual petals (Fig. 88).Anthers are basifixed, elongate (almost linear), andslightly introrse with a narrow connective and occa-sionally with a minute protrusion (Fig. 49). A shallowapical furrow is present between the thecae on theventral side and less pronounced or absent on the dor-sal side (Figs 12B,53). Anther dehiscence is by an api-cal pore separating the tips of the ventral and dorsalconfluent pollen sacs (Fig. 53). Filaments are oftenbroader than thick. The three to four carpels areunited up to below the stigmas, with a superior ovary;they are of angiospermy type 3 (Fig. 12A–J,A¢–G¢). Thebases of individual styles are laterally compressed,and at the level of the ovary prominent dorsal medianribs are present. The ovary is synascidiate for fourfifths of its length, extending above the placenta(Fig. 12F–J,F¢,G¢). Stigmas are punctiform, secretoryat anthesis; they are closely associated and form asingle, unicellular papillate surface (Fig. 93). The ven-tral slit does not extend up to the stigma (Fig. 12A,A¢)and is postgenitally fused or unfused in the symplicateregion of the style (Fig. 12B–D,B¢–D¢). A gap is presentbetween the styles directly below the stigmas, at thelevel where the ventral slit is not present. The stylarcanal extends up to the lower or mid-style. The ventralslit, gap between the styles, and the stylar canals arelined by one or two cell layers of PTTT. Directly belowthe stigmas a compitum seems to be present, andagain in the symplicate zone of the ovary. In the ovarylocules PTTT is continuous in the ventral slits (one totwo cell layers) and flanking them on both sides (onecell layer) in the symplicate zone and along the pro-nounced internal ventral furrow in the synascidiatezone (Fig. 12F,G,F¢,G¢), continuing around the funiclein the placental zone. Each locule contains c. 13–19ovules. Placentation is lateral, at mid-length of theovary (Fig. 65G). In the upper synascidiate zone, pla-centation is in two rows on either side of the internalfurrow, while in the lower synascidiate zone thisincreases to three: two ovules are on the same side(Fig. 12G,G¢,65G). Ovules are bitegmic, crassinucellar,and normally anatropous, horizontal or oblique. Themicropyle is zig-zag-shaped or it is a longitudinal slitformed by both or the inner integument, and depend-ing upon the position of the ovule within the locule itsmicropyle may contact either its own funicle or thefunicle of an adjacent ovule that shares the same pla-cental region. Both integuments are lobed. The outerintegument is six to eight cell layers thick, the innersix to nine. An endothelium is differentiated on theinner integument. One to several ovules at the periph-ery of the placenta are abnormal: the outer integu-ment is separate from the rest of the ovule, which issterile. A nectary disc is present between the corolla

and gynoecium, with the stamens inserted in it(Fig. 12I–L). The disc resembles a cog-wheel due to theshape of the nectary lobes, which extend more verti-cally than horizontally (Figs 12J,K,64). A nectary lobeprotrudes into each of the two chambers of individualpetals (Fig. 12J,K). The zone with the nectary repre-sents an androgynophore. A floral cup is not formed.

Anatomy. Sepals have three main (and one to two sec-ondary) vascular bundles, and three vascular traces inthe floral base (Fig. 12). Petals have three main tracesand five main bundles. The central bundle divides intothree, to serve each of the three petal lobes. Up to tensecondary bundles form a network with the main bun-dles. Stamens have a single bundle. Carpels have adorsal bundle that extends to the symplicate regionbelow the stigmas, where it consists mainly of xylemelements, and two shorter lateral bundles. In thestyle, two secondary lateral bundles are present. Thenumber increases basipetally, and in the ovary up to18–23 are present. They form a network with the mainbundles in the ovary wall. Those in the septa betweenthe carpels may form synlaterals, which connect to oneof the main lateral bundles. The ovules are served bycomplex bundles connected with the main laterals. Inthe lower region of the placenta the lateral bundlesform a ring of six large lateral bundle complexes (in a3-merous gynoecium) in the centre of the gynoecium.At the base of the locules and below, secondary carpelbundles within the ovary wall unite and join the dor-sal bundles and neighbouring stamen traces. Epipeta-lous stamen traces of the same sector unite to form acomplex bundle, and episepalous stamen traces jointhe central carpel complex directly. The lateral petalbundles in individual petal flanks unite. The medianpetal/epipetalous stamen complexes fuse with the lat-eral sepal traces and join the central complex bundles.The lateral petal traces of adjacent petals fuse to themedian sepal trace. These complexes form a girdlearound the central complex but lower down remain asfive separate complexes before they join the centralcomplex to form a uniform stele. The nectary hasmany branching phloem strands, which join the near-est stamen traces.

Histology. Stomata (not raised) are present on thedorsal side of the sepals and petals, and on thenectary. Petals have large-celled tissue with largeintercellular spaces. Endothecium is continuous overthe dorsal and ventral side of the anther, it has normaldifferential wall thickenings (Fig. 56J). The nectarycontains portions of cytoplasm-rich tissue (interruptedby more vacuolate areas), except for the epidermis andhypodermis. Unicellular lignified hairs are presenton all floral organs: on the sepals (hairs tanniferousand twisted), petals (especially ventral ridge), anthers



(hairs broad-based), filaments, gynoecium, andnectary (Fig. 64). Unicellular lignified hairs and short,glandular hairs (1-celled stalk, 2-celled head) arepresent inside the ovary locule (Fig. 95). Tanniferoustissue is absent (apart from the hairs mentioned).Cells with oxalate crystals are present in sepals,anther, ovary, nectary and floral base; cells withdruses were found in the sepals and ovary.

Sloanea macbrydei

Morphology. Flowers are bisexual and polyandrous(Fig. 13). The four thick sepals have a broad base and

a pointed apex. They are valvate; there is postgenitalcohesion by hairs. Petals are absent. The c. 75 stamens(two flowers counted) are arranged in four series, theouter series shorter and often lacking pollen sacs(Fig. 48). Anthers are basifixed, almost sessile, elon-gate, sagittate, latrorse, with a narrow connective anda protrusion. Dehiscence is by a short longitudinal slitrestricted to the apex of each theca. The two carpelsare united up to the upper style and very closely asso-ciated above (partially postgenitally connected but notfused); with a superior ovary; they are of angiospermytype 3 (Fig. 13A–G,C¢–F¢). The ovary is synascidiate

Figure 13. Sloanea macbrydei (Elaeocarpaceae). Floral bud, TS series. A,B, level of anthers and free styles. C, uppersymplicate zone of ovary, ventral slits postgenitally fused (dotted lines). D, symplicate zone at level of placentae. E,F,synascidiate zone at level of placentae. G, ovary below level of placentae. H, level of very short androgynophore. I–K, floralbase. C¢–F¢, higher magnification of gynoecium for C–F. Scale bars = 2 mm in A–K; 1 mm in C¢–F¢.

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for two thirds of its length, extending up to the mid-region of the placenta (Fig. 13E–G,E¢,F¢). A short dor-sal rib is present in the ovary locule (Fig. 13E,F,E¢,F¢).The small stigmas are terminal and unicellular papil-late. The ventral slit extends up to the stigma. In thelower plicate zone it is postgenitally closed by cellulardentation. In the symplicate zone, it is fused by peri-clinal divisions. A short stylar canal extends up to thelower symplicate zone. In the plicate zone, three to fivecell layers of PTTT line the ventral slit; in the sympli-cate zone PTTT is restricted to the region between thedorsal and ventral carpel bundles (one to two cell lay-ers); it is present in the ovary locule, along the two pla-centae, and seemingly also below them in medianposition in the synascidiate zone. A compitum seemsto be lacking. Eight collateral ovules per carpel arearranged in two vertical lines; they fill the locules(Fig. 65H). Ovules are bitegmic, crassinucellar, andanatropous. The irregularly slit-shaped micropyle isformed by the inner integument; it faces obliquelyupwards, towards the placenta. Both integuments arelobed. The outer integument is five to six cell layersthick, the inner six to nine. An endothelium is notdifferentiated. A nectary disc is absent. However thelower ovary has prominent protuberances with mer-istematic or secretory tissue, which may develop intospines in fruit (Fig. 13C–G,C¢–F¢). This zone at theperiphery of the ovary wall is richly vascularized withphloic strands and it should be studied to determinewhether or not it is secretory. A short gynophore ispresent and a partial androgynophore (Fig. 13H). Onthe convex floral base the inner stamens are higherthan the outer (Fig. 48). Sepal margins remain freebelow the floral base (Fig. 13I,J). A floral cup is notformed.

Anatomy. Sepals have c. eight main (and c. 7–13 addi-tional secondary) vascular bundles, and c. eight vas-cular traces in the floral base (Fig. 13). At this level,lateral bundles of adjacent sepals unite into synlater-als and secondary bundles unite with neighbouringbundles. Stamens have one bundle. Carpels have abroad dorsal bundle with two xylem portions and twomain lateral bundles extending up to the free stylarregion ending as a band of mainly tracheids below thestigma. Four to five additional lateral bundles arepresent above the ovary, and up to 16–18 in the ovary,which form a network with the main bundles. Thealready mentioned vascular bundles of the protuber-ance zone of the ovary wall branch from the main andsecondary lateral bundles. The lateral bundles of adja-cent carpels unite into synlaterals in the lower sym-plicate zone of the ovary. In the synascidiate zone thesynlaterals unite to form a large central vascular com-plex between the carpels. The ovules are supplied bybranches from the lateral bundles, the synlaterals,

and the central bundle complex. Below the ovary loc-ules, the central complex of lateral bundles is sur-rounded by a peripheral ring, which includes thedorsal carpel and secondary carpel bundles. In theconvex floral base, stamen traces partly unite withneighbouring ones and join neighbouring secondarycarpel bundles. Secondary carpel bundles also fusewith the central bundle complex. In the floral base, aprogressively widening ring of complex bundles ispresent in the centre of the flower. Sepal complexesunite and generally three complexes per sepal join thisring.

Histology. Stomata are present on the dorsal sepalsurface, those near the tip are raised. Anther epider-mal cells are distinct and are radially elongate. Endo-thecium of evenly thickened cell walls is continuousover the dorsal and ventral side of the anther and ispresent in the entire connective region, but ceasing atthe stomium (Fig. 56K,L). Unicellular lignified, tan-niferous hairs are present on the sepals, stamen fila-ment and lower style and ovary. Those on the anthersare not tanniferous and are sunken into the antherepidermis. The tissue of the sepals has large intercel-lular spaces. The distribution of tanniferous cells inthe androecium is distinct, concentrated in the epider-mis of those regions of the stamen not protected byother stamens, such as the dorsal epidermis of theouter whorl of stamens and anther tips. Tanniferouscells are also present in the epidermis of the ovary.Cells with oxalate crystals and druses are present inthe sepals, stamens, and ovary.

Vallea stipularis

Morphology. Flowers are bisexual. The perianthwhorls are 5-merous (Fig. 14). Sepals are thick, with abroad base and a pointed apex; they are valvate; thereis postgenital cohesion by hairs (Fig. 24). The largepetals have a narrow base and are incised (one fifth oflength) to form three lobes: a longer central lobe andtwo shorter involute lateral lobes (Fig. 57J); aestiva-tion is cochlear. The c. 37–47 stamens are arranged intwo series. Filaments of the inner whorl are thickerand broader than those of the outer. Anthers are basi-fixed, elongate, x-shaped, and slightly introrse, with abroad connective and without a protrusion. Dehis-cence is by a short longitudinal slit restricted to theapex of each theca (Fig. 52). Filaments are longer thananthers in bud and have a distinct hair-pin bend justbelow the anther directed to the floral centre. Thethree to five (epipetalous) carpels are united up to theupper style, with a superior to very slightly inferiorovary; they are of angiospermy type 3 (Fig. 14A–H,C¢–F¢). The ovary is synascidiate for two thirds of itslength, extending up to the lower half of the placenta(Fig. 14F,G,F¢). Stigmas are capitate and unicellular



Figure 14. Vallea stipularis (Elaeocarpaceae). Floral bud, TS series. A, level of sepals, petals and free styles. B, symplicatezone of style. C,D, upper symplicate zone of ovary. E, symplicate zone at level of placentae. F, synascidiate zone at levelof placentae. G, upper level of nectary disc (shaded). H–L, floral base. A¢-F¢, higher magnification of gynoecium for A–F.Scale bars = 2 mm in A–L; 1 mm in B¢–F¢.

BA

G

F

E´

E

D´

D

C´

C

F´J K L

IH

B´



papillate; secretion was not found. The ventral slitextends up to the stigma. A gap lined with tanniferouscells is present in the upper syncarpous part of thestyle. A stylar canal is present in each carpel in thelower style. PTTT is present in the inner part of eachventral slit (one dark-staining cell layer) and along theplacentae (one to two cell layers). Although the narrowventral slits communicate with each other it is doubt-ful whether there is a compitum, because the epider-mis stains less darkly in the more central area of thegynoecium. Two lateral ovules per carpel are posi-tioned one ovule partly above the other. They arebitegmic, crassinucellar, and anatropous, with acurved chalazal appendage. The longitudinal slit-likemicropyle is formed by both integuments; it is directedsidewards and downwards in the upper ovules, andsidewards and upwards in the lower ovules. Bothinteguments are lobed. The outer integument is fourcell layers thick, the inner six to eight. An endothe-lium is present on the inner surface of the inner integ-ument. A flat nectary disc surrounds the gynoecium(Fig. 14G) and slightly protrudes between the innerseries of stamens. Sepal margins remain free belowthe floral base (Fig. 14I–K). A floral cup is not formed.

Androecium development. Episepalous stamen pri-mordia form five crescent-shaped groups (Figs 32,33).The stamens in the middle of each group are initiatedfirst, followed successively by more lateral ones, andfinally by a more dorsal median one. Only now epipe-talous stamens (in single or double position) areinitiated. At about this time additional episepalousstamens next to the dorsal median one are initiated.Androecium development is centrifugal.

Anatomy. Sepals have five (to seven) main (and two tofour secondary) vascular bundles, and five vasculartraces in the floral base (Fig. 14). Petals have threemain bundles, each serving one of the three petallobes. They diverge from one trace below the petalattachment. In addition, a number of secondary bun-dles are present in each petal lobe. Stamens have asingle bundle. Carpels have a dorsal bundle thatextends up to the free stylar region and ends in a bandof mainly tracheids below the stigma. The two shortermain lateral bundles extend up to the symplicate zoneof the style. Above the ovary, two to four secondarybundles are present, this number increases basipe-tally in the ovary. They form a network with the mainlateral bundles and with the dorsal bundle. At the topof the ovary locules, secondary bundles from adjacentcarpels unite into synlaterals in the septa and form acomplex with the main lateral bundles at the innerend of the same septum. This complex supplies theovules of adjacent placentae. In the synascidiate zone,these complexes unite into a central ring of complex

bundles. In the convex floral base, neighbouring sta-men traces unite, typically forming complexes in anepipetalous or an episepalous position. Below theovary locules, neighbouring secondary carpel bundlesjoin either the central carpel bundle complex orneighbouring stamen complexes. The sepal bundlesbetween the median and main lateral bundles joineither of these bundles to form median and lateralsepal complexes. Epipetalous stamen complexes joinpetal traces, and together they join the lateral tracesof adjacent sepals, lower down they are joined by thedorsal carpel trace, and together they fuse to the cen-tral bundle complex. The episepalous stamen com-plexes join the median sepal traces, and this complexis the lowest one to join the central bundle complex. Inthe nectary disc, numerous small (primarily) phloicstrands are present, which branch from neighbouringstamen and secondary carpel bundles.

Histology. Stomata are present on the dorsal sepalsurface (raised near the tip). They were not found onthe nectary. Cytoplasm-rich tissue is present in por-tions in the nectary disc (not in the epidermis). In thenearly anthetic floral buds studied, endothecium wasnot differentiated in the anthers. The surface of theovary locule is lined with conspicuously radially andtangentially enlarged cells. Unicellular thin-walledhairs are present on the ventral side of the petals andon the stamen filament, nectary, and in the ovary loc-ule. Those on the ventral side of the sepals and on theanthers are thick-walled and tanniferous (Fig. 91).Tanniferous cells are localized around the vascularbundles in the sepals, petals and stamen filaments.Cells with oxalate crystals and druses are present inthe petals, and in the anther connective.

TREMANDRACEAE

Platytheca galioides

Morphology. Flowers are bisexual, 5-merous, and(ob)diplostemonous (a distinction between obdiploste-monous and diplostemonous is problematic becausethe gynoecium is 2-merous) (Fig. 15). As the flowersare pendant, the sepal base is bulged upwardstowards the pedicel (Fig. 15M). Sepals have a broadbase, and a pointed apex; they are thin, valvate in theupper region, and revolute-valvate below; there ispostgenital cohesion mainly by cuticular dentation(some cellular dentation), and by hairs (Fig. 25). Thepetals are involute and induplicately valvate, theyhave a narrow base and are tapering towards theacuminate tip (Fig. 57K); the lower part of each petalblade surrounds the lower part of the stamen of thesame radius (Fig. 15C–I). Stamens are straight in bud(Fig. 50). Anthers are basifixed (almost sessile) and



sagittate, with a broad connective and a long terete,snorkel-like sterile part (even longer than the fertilepart) (Fig. 50). Each anther dehisces by a single apicalpore at the end of the sterile part (Fig. 54). Near thebase, the anthers are extremely introrse so that thefour pollen sacs are arranged in one plane (Fig. 15D–G). Episepalous anthers are longer with a narrowersterile part, and a slightly broader filament than thoseof epipetalous ones. The two carpels are free in theslender style but closely associated up to the stigmaand may be postgenitally coherent; they have a supe-rior ovary; they are of angiospermy type 2 (Fig. 15A–I). The style is conspicuously curved at its base. Theovary is completely synascidiate (Fig. 15E–I). The twostigmas are punctiform and form a single, slightly flat-

tened, but narrow, stigmatic surface, the unicellularpapillae of both carpels are bent over the stylar canaland are interlocking. In addition, the carpel tips areclosed by secretion. Below the stigma the ventral slitis widely gaping along the entire style. The ventral slitis narrow (but not fused) only in the short symplicatezone at the base of the style where a stylar canal isalso present. In this zone a short compitum seems tobe present. PTTT of one cell layer thick lines the ven-tral slit and continues on either side of the ventralfurrow down to the apical median placenta. A single,median, large, pendant, triangular (in TS) ovule fillseach locule (Fig. 100). Ovules are bitegmic, apparentlycrassinucellar, although the nucellus is thin,anatropous and antitropous, with unicellular hairs

Figure 15. Platytheca galioides (Tremandraceae). Floral bud, TS series. A,B, level of anther snorkels and free styles. C,level of induplicate petals, anthers and styles. D, upper symplicate zone of ovary. E, upper synascidiate zone of ovary abovelevel of placentae. F, synascidiate zone at level of placentae. G, ovary below level of placentae. H,I, ovary below level ofovules. J, level of androgynophore. K–N, floral base (sepals bulging below floral base in M). Scale bar = 1 mm.

HGF

EDCB

A

J K L M

I

N



densely covering the ovule surface at anthesis(Figs 73,100,101). The micropyle is directed towardsthe ceiling of the locule; it is a longitudinal slit, formedby both integuments. Both integuments are lobed. Theouter integument is expanded into a funnel-like struc-ture surrounding a short obturator (Figs 71,73). A dis-tinct gap is present between the two integuments(Fig. 73). The outer integument is four to five cell lay-ers thick, the inner nine to 12. The ovary wall has alongitudinal furrow on the dorsal sides and thereforethe wall is thin in this region. There is a short gyno-phore and a very short androgynophore (Fig. 15J). Anectary seems to be lacking. The free sepal marginsextend somewhat below the floral base (Fig. 15L). Afloral cup is not formed.

Anatomy. Sepals have three main (and one to two sec-ondary) vascular bundles, and three vascular traces inthe floral base (Fig. 15). The main bundle extends upto the pointed tip of the sepal, the other bundles areshorter. Petals have three vascular traces and threevascular bundles, plus five to eight secondary bundles,which branch from the main bundles above the floralbase. Stamens have a single bundle. In the carpel thethin dorsal median bundle (in the plane where thefruit later dehisces) and two main thick lateral bun-dles extend up to the lower free stylar region and endin the stigma as a band of mainly tracheids (trache-oids). In the short symplicate zone, two to three sec-ondary bundles may be present connected with themain bundles, and in the ovary up to six. In the centreof the septum above the placenta, a ring of poorly dif-ferentiated vascular tissue is present surrounded bythe lateral bundles. Lower down the laterals are alsoincorporated into this ring, and this ring supplies thesingle ovule in each locule. The ovular bundle dividesin the chalaza into several branches, which lead intothe base of the inner integument. Below the placentathis central bundle complex divides into two largesynlateral complexes. Below the ovary locules, thesecondary carpel bundles join the dorsal carpel bundleor neighbouring secondary bundles. Thus, one to twolarge secondary bundle complexes may also bepresent. The dorsal bundles join the central bundlecomplex, while the secondary carpel complexes unitewith neighbouring stamen bundles, such that thecentral complex is surrounded by ten peripheral sta-men bundles (or complexes). The lateral petal bundlesof adjacent petals fuse with the median sepal trace,and the median petal bundle unites with the lateralsepal traces of adjacent sepals. They form anotherseries of traces around the two central series. Theepipetalous stamen trace complex is joined by thecarpel trace complex of the same radius, and thesetogether join the epipetalous sepal and petal complex,while the episepalous stamen complex is joined by the

carpel bundle complex of the same radius, and thesejoin the episepalous petal and sepal complexes.Together they form a central stele.

Histology. The dorsal sepal epidermis contains cellswith thickened (mucilaginous) inner tangential walls(Figs 25,28). Such cells continue downwards on thepedicel. At the margins of the sepals towards the base,multicellular, multiseriate protuberances are present.The sepals, petals, stamen filaments, and tissue belowthe gynoecium contain large intercellular spaces. Sto-mata are sparse (and sunken) on the dorsal sepal epi-dermis, more abundant on the ventral epidermis. Inthe anthers, in the place of a normal endotheciumlayer, a cell layer with thickened (lignified) outer tan-gential walls form a continuous cylinder in the sub-epidermis, especially in the snorkel (Fig. 56M). Thecells of the epidermis also have thickened outer walls.In the mature anthers this cylinder and the epidermisare the only remaining cell layers in the snorkel. Thedorsal epidermis of the pollen sacs has enlarged papil-late cells. Unicellular lignified hairs are present onthe sepals, anthers (Fig. 92), and ovary. Unicellularthin-walled hairs are present on the ventral flanksof the sepals, the anthers, and on the ovule surface(Figs 71,100,101). Those on the ovule are expanded atthe base (sausage-like) and extremely narrow at thetip. Unicellular hairs with a conspicuous multicellularpedestal are present on the dorsal side of epipetalousanthers (Fig. 50). Tanniferous cells are concentratedin the dorsal hypodermis of the lower region of thesnorkel of the anthers, and in the outer hypodermis ofthe lower style. Cells with oxalate crystals and drusesare present in the anther connective, between theovary locules, and in the floral base.

Tetratheca thymifolia

Morphology. Flowers are bisexual, and 4-merous(gynoecium 2-(3)-merous) (Fig. 16). Sepals have abroad base and a pointed apex; they are not postgen-itally coherent (Fig. 89); aestivation is revolute-valvate. In older buds, petals are longer than sepals,and thus they are the protective organs (Figs 16A,89).The elongate petals have a narrow base (Fig. 57L);they are involute and induplicately valvate; they havea papillate epidermis. The androecium has a singlewhorl of eight stamens in double positions (Figs 16B–H,51). As all eight stamens are almost equidistantfrom each other, it is unclear whether the double posi-tions are episepalous or epipetalous. The two anthersin front of each petal are enwrapped in the petalflanks (see also Thompson, 1976) (Figs 16B–F,90).Anthers are large, introrse, basifixed, almost sessile,elongate, and broader at the base than at the tip, witha thin connective and without a protrusion (however,



Figure 16. Tetratheca thymifolia (Tremandraceae). Floral bud, TS series. A, level of induplicate petals and free styles. B,level of sepal tips, apical pore of anthers and symplicate style. C, base of symplicate style. D, upper symplicate zone ofovary. E, synascidiate zone at level of placentae. F, synascidiate zone near base of placentae. G, level of stamen filaments,and ovary below level of ovules. H, end of androgynophore. I–L, floral base. D¢, higher magnification of gynoecium for D,ventral slits postgenitally fused (dotted lines). Scale bars = 1 mm in A–L; 400 mm in D¢.

KJI

HGF

DCBA

D´L

E

in other species of the genus a snorkel-like extensionis present as in Platytheca; cf. Thompson, 1976)(Fig. 51). Individual pollen sacs are not bulging andlack distinct furrows between them (Fig. 16C–F).Each anther dehisces by a single transverse apicalpore, which develops by decay of tissue between theoriginally non-confluent thecae (Fig. 55). The carpelsare postgenitally united up to the stigma, with a supe-rior ovary; they are of angiospermy type 3 (Fig. 16A–G,D¢). The symplicate zone is short, present only at thebase of the style, or it also includes the uppermost partof the ovary (Fig. 16D,D¢). The ovary may be com-pletely synascidiate (anthetic flower, Maranoa Gar-dens collection) or for three to four fifths of its length,and up to the upper four fifths of the placenta(advanced bud, collection E 6144) (Fig. 16E–G). Due to

the close association of the carpels, a single puncti-form stigmatic surface, with long, unicellular papillaeis present (Fig. 94). Secretion is present in advancedbuds. The ventral slit of the contiguous carpels is gap-ing and forms a single central canal. The ventral slit isnarrow only at the base of the style; individual stylarcanals are present in this region, secretion may also bepresent in the canals and ventral slits. PTTT extendsas a single weakly differentiated cell layer lining theventral slit throughout the style, down to the ovarylocules on either side along the remaining inner partof the ventral slit to the placentae. A compitum seemsto be present, extending through the entire style.Placentation is lateral and two alternating ovulesare present per locule, one partly above the other(the range is one to five at genus level; Thompson,



1976). Ovules are bitegmic, crassinucellar (see alsoBoesewinkel, 1999), and anatropous, with a pro-nounced, hooked chalazal appendage (see alsoThompson, 1976; Boesewinkel, 1999); they are pen-dant, with the micropyle directed upwards; the micro-pyle is a longitudinal slit. Both integuments are lobed.The outer integument is four cell layers thick, theinner six to seven (in T. pilosa c. ten; Biddle & Chris-tophel, 1978). An endothelium is not differentiated. Anectary is absent. An extremely short gynophore andandrogynophore are present (Fig. 16H). Sepal mar-gins remain free below the floral base (Fig. 16I,J). Afloral cup is not formed.

Anatomy. Sepals have three main (and c. three to foursecondary) vascular bundles, and three vasculartraces in the floral base (Fig. 16). Petals have threevascular traces, which divide into 18–23 bundles inthe blade. Stamens have a single bundle. In the car-pel, the thin dorsal bundle (it is in the plane wherethe fruit later dehisces) extends up below the stigmaand ends in a band of mainly tracheids. The two mainlateral bundles are shorter. Two to four secondarybundles may be present above the placenta. The ovarylocules are surrounded by an almost continuous sys-tem of secondary lateral bundles forming a networkwith the main bundles. In the placenta, the main lat-eral bundles of adjacent carpels unite into synlateralsthat supply the upper ovule of each locule. The syn-laterals join to form a central bundle complex thatsupplies the lower ovule of each locule. Below thelocules, secondary lateral bundles join the dorsalbundles, and together they join the central bundlecomplex. In the floral base stamen traces are groupedas a regular series around the central carpel bundlecomplex. The lateral bundles of adjacent petals fusewith the median sepal trace, and this bundle complexjoins the central bundle complex. The lateral traces ofadjacent sepals, the median petal trace and the twoepipetalous stamen traces of the same radius fuse andjoin to the central bundle complex. Finally the largemedian sepal trace/lateral petal bundle complex joinsthe central bundle complex and a stele is formed.

Histology. In the sepals the dorsal epidermis (and to alesser extent the ventral epidermis) contains cellswith thickened (mucilaginous) inner tangential walls(Fig. 29); such cells continue downwards to directlyabove the pedicel. Petals are papillate on both surfacesand have large intercellular spaces in the mesophyll.The hypodermal cell layer of the anthers is not differ-entiated as a normal endothecium; it has cells withthick, lignified outer tangential and lateral walls,which form a continous ring around the anther(Fig. 56N). Carpel epidermal cells have a thickened

cuticle near the stigma; they are papillate in the mid-to lower style. Raised stomata are present on the dor-sal surface of the sepals, especially concentrated nearthe tip. Unicellular lignified, tanniferous hairs arepresent on the sepals, lower style and ovary and insidethe ovary locules. Tanniferous cells are present in allorgans (almost absent in the petals). Cells containingoxalate crystals and druses are present in the petals,and anthers; druses are abundant in the base of theandroecium and gynoecium.

DISCUSSION

GENERAL ROSID (CORE EUDICOT) FEATURES

IN OXALIDALES

Flowers of the bulk of Oxalidales have a number offeatures that are of general distribution in rosids (orbasal core eudicots) and therefore, are probably plesi-omorphic in Oxalidales (or synapomorphic for coreeudicots), although this requires testing in a phyloge-netic analysis. For example, flowers are commonly 5-merous; the perianth has sepals and petals; sepals areacute, with a broad base and three vascular traces;petals have a broad, rounded plate and a narrow base,and one vascular trace (for other core eudicots, seee.g. Eames, 1931; Eckert, 1966; Endress, 1967, 1994;Rohweder, 1970); stamens are in two whorls; obdiplos-temony is common (Dickson, 1864; Eckert, 1966;Gelius, 1967; Rohweder, 1970; Klopfer, 1973; RonseDecraene & Smets, 1993, 1995, 1996, 1998); theobdiplostemonous condition is correlated with thephenomenon that epipetalous stamens tend to besmaller (shorter, thinner, narrower) than episepalousones (Eckert, 1966), in the extreme case sterile or evenlacking; anthers are dorsifixed and introrse (see, e.g.Endress & Stumpf, 1991); there is an extensive rangeof carpel union, from completely free to almost com-pletely (congenitally) united, but commonly the car-pels are free at least in the uppermost part of thestyle. The presence of two carpels is common in somebasal eudicots (Papaveraceae, Sabiaceae, Buxaceae,Gunneraceae; Drinnan, Crane & Hoot, 1994; Endress& Igersheim, 1999; von Balthazar & Endress, 2002)and basal core eudicots (Caryophyllales, Saxifragales;Endress & Igersheim, 1999). In basal core eudicots itmay be a plesiomorphic feature, inherited from basaleudicots. However, as there are many basal rosidswith 5-merous (isomerous) or 3-merous gynoecia, thisfeature is ambiguous. If it were plesiomorphic, onemay even ask whether the dimerous condition in thegynoecium has been more conservative than dimery ofthe other organ categories, which have become pre-dominantly pentamerous in the core eudicots, andwhether only somewhat later the gynoecium was also‘isomerised’. However, it seems more probable that the



dimerous gynoecia found in Oxalidales are reversalsfrom pentamerous ones. Pollen is tricolpate or mostlytricolporate, often with reticulate exine, with themeshes much smaller near the apertures (Oxali-daceae: Huynh, 1969; Oltmann, 1971; Serbanescu-Jitariu, Radulescu-Mitroiu & Radulescu, 1974; Yunus& Nair, 1989; Connaraceae: Eimunjeze, 1976;Dickison, 1979; Lemmens, 1989; Brunelliaceae:Ludlow-Wiechers, 1986; Orozco, 1991; Cephalotaceae:Erdtman, 1952; Pastre & Pons, 1973; Hideux &Ferguson, 1976; Cunoniaceae: Hideux & Ferguson,1976; Crepet, Nixon & Feldman, 1991; Elaeocar-paceae: Tang & Wu, 1990; Tremandraceae: Erdtman,1952). The embryo is commonly embedded in abun-dant oily endosperm; it is small or large (e.g.Schellenberg, 1910; Netolitzki, 1926; Lopez-Naranjo& Huber, 1971; Corner, 1976). Inflorescences arethyrso-paniculate systems (e.g. Knuth, 1931;Veldkamp, 1971, for Oxalidaceae; Leenhouts, 1958, forConnaraceae; Diels, 1930, for Cephalotaceae; Orozco& Weberling, 1999, for Brunelliaceae and Cunoni-aceae) , but apparently rather racemose in Elaeocar-paceae and Tremandraceae, and in some Cunoniaceae,such as Cunonia and Weinmannia; Bradford, (1998).Pedicels are articulated (Oxalidaceae, Veldkamp,1967; Robertson, 1975; Connaraceae, Leenhouts,1958; Brunelliaceae, Cuatrecasas, 1970; Cunoniaceae,Elaeocarpaceae, pers. obs.).

FEATURES OF MORE SPECIFIC INTEREST IN OXALIDALES (POTENTIAL SYNAPOMORPHIES)

General featuresA number of features of Oxalidales are less commonlyfound in other orders of the rosids (or other basal coreeudicots), some may also be plesiomorphies for rosids.However, at least part of these features may later bedetermined to be synapomorphies of Oxalidales (or,perhaps, eurosids I, sensu APG, 1998).

Isomery in all floral whorls is relatively com-mon in Oxalidales, such as in Oxalidaceae, mostConnaraceae, Brunelliaceae, Cephalotaceae, andAcsmithia and a few other Cunoniaceae (cf. Engler,1930c). This is also true for Anisophylleaceae (cf.Matthews et al., 2001; Schönenberger et al., 2001).Only in some Connaraceae, in the majority of Cunon-iaceae, and in the Elaeocarpaceae/Tremandraceaeclade is the gynoecium fewer-parted. As mentionedabove, flowers are most often 5-merous (at least in theperianth if flowers are not isomerous) but 4-mery isalso often present. In fact, there is much fluctuationbetween four and five carpels, often within genera,species or even individuals. More unusual conditionsalso occur. In Cephalotaceae merism is normally six,sometimes also in Brunelliaceae (Cuatrecasas, 1970).In Connaraceae (species of Pseudellipanthus), 3-

merous flowers occur (Schellenberg, 1938). In Cunon-iaceae merism may be increased (six in Belangera,Engler, 1930c; five to nine in Bauera, Dickison, 1975a)or decreased (three in Pancheria and Vesselovskya,Engler, 1930c; Rozefelds, Barnes & Pellow, 2001). InElaeocarpaceae it may also be as high as 11 (Smith,1954) or as low as three, both in Sloanea. A floral cupis formed in Cephalotaceae (Fig. 17), Ceratopetalum(Fig. 18), Schizomeria (Cunoniaceae), and Aristotelia(Elaeocarpaceae) (very short) (Fig. 19). A shortandrogynophore is present in Oxalidaceae(Figs 1J,2I,J,3J), Connaraceae (Figs 4G,H,5F) (seealso Dickison, 1971; Jongkind, 1989), Brunelliaceae(Fig. 6I); very short also in Cunoniaceae (Acsmithia,Fig. 8H,I; Geissois, Fig. 9G,H), Elaeocarpaceae (Crino-dendron, Fig. 12K; Sloanea, Fig. 13H), and Treman-draceae (Platytheca, Fig. 15J; Tetratheca, Fig. 16H).Floral tissues are commonly highly tanniferous. Uni-cellular, lignified hairs are common on various floralorgans.

Foliage leaves are often pinnate, such as in Oxali-daceae, Connaraceae, Brunelliaceae and Cunoniaceae;in the same families trifoliolate leaves also occur. Insome Elaeocarpaceae, pinnate leaves occur in juvenileplants (Hyland & Coode, 1982 ). The highly differ-entiated pitcher leaves of Cephalotaceae have alsobeen interpreted as pinnate with regard to theirdevelopment (Froebe & Baur, 1988). Epicuticularwaxes on foliage leaves are often in the form of waxscales that are arranged in rosettes (Oxalidaceae,Tremandraceae, Ditsch & Barthlott, 1997;Connaraceae, Fehrenbach & Barthlott, 1988;Ditsch, Patha & Barthlott, 1995; Brunelliaceae,Elaeocarpaceae, Ditsch & Barthlott, 1994).

CalyxIn several taxa the sepals are congenitally united atthe base (Averrhoa of Oxalidaceae; Rourea solanderiof Connaraceae, cf. Jongkind, 1989; Cephalotaceae;Acsmithia, Geissois, Davidsonia of Cunoniaceae; Crin-odendron of Elaeocarpaceae, see also Bricker, 1991).However, in the majority they are not congenitallyunited, and their margins are decurrent at the floralbase. This is also the case in Anisophylleaceae(Matthews et al., 2001). In Oxalidaceae (see alsoKnuth, 1930, 1931) and Connarus (Connaraceae)the sepals are quincuncial-imbricate (according toSchellenberg, 1938, this is the normal pattern in Con-naraceae; for Oxalidaceae, see also Narayana, 1966);in Crinodendron (Elaeocarpaceae), although congeni-tally united, they are short and open. But in mostother Oxalidales they are valvate. In sepals with val-vate aestivation, there is postgenital connection of agreater or lesser degree, by hairs (Figs 20–25), cellularor cuticular dentation. Only in Tetratheca (Treman-draceae) such a bond is lacking. Combinations



between imbricate and valvate areas in the calyx arealso present in some taxa. Valvate calyces are alsocommon in Anisophylleaceae (Matthews et al., 2001).Sepal tips are incurved in bud in Cnestis (Con-naraceae), Acsmithia (Cunoniaceae), and also in Anis-ophyllea (Anisophylleaceae). Sepal tips are hooded inCephalotaceae and Schizomeria (Cunoniaceae).

Sepals have at least three main vascular bundlesand traces, in some Oxalidaceae and Elaeocarpaceaemore than three. Additional secondary, minor bundlesare always present.

Sepals normally have stomata on the dorsal side. Inmany Oxalidales such stomata are raised like short

chimneys, especially at the sepal tip; this was foundin Biophytum (Oxalidaceae); Cnestis (Connaraceae);Cephalotaceae; Ceratopetalum and Davidsonia(Cunoniaceae); Aristotelia, Sloanea, and Vallea (Elaeo-carpaceae); and Tetratheca (Tremandraceae); the samewas found in Anisophylleaceae (Matthews et al.,2001). In Biophytum (Oxalidaceae) and Platytheca(Tremandraceae), stomata were found on both sepalsurfaces.

In a number of Oxalidales the sepals contain idio-blasts with a thickened (mucilaginous) inner tangen-tial wall (mostly epidermal, more rarely hypodermal)(Figs 26–29), such as in Cnestis and Connarus (Con-

Figures 17–25. Figs 17–19. TS floral buds at level of floral cup. Inner surface of floral cup with nectary indicated byarrowhead. Fig. 17. Cephalotus follicularis (Cephalotaceae). Fig. 18. Ceratopetalum gummiferum (Cunoniaceae). Fig. 19.Aristotelia chilensis (Elaeocarpaceae). Figs 20–25. TS floral buds, postgenital coherence of sepal margins by hairs. Regionof sepal coherence indicated by arrowhead. Distinctive epidermal cell with unequally thickened, mucilaginous innertangential wall indicated by arrow. Fig. 20. Cnestis ferruginea (Connaraceae). Fig. 21. Brunellia standleyana (Brunelli-aceae). Fig. 22. Geissois biagiana (Cunoniaceae). Figs 23,24. Elaeocarpaceae. Fig. 23. Aristotelia chilensis. Fig. 24. Valleastipularis. Fig. 25. Platytheca galioides (Tremandraceae). Scale bars = 1 mm in 17–19; 100 mm in 20–25.



Figures 26–33. Figs 26–29. TS sepals, showing distinctive epidermal cells with a thickened, mucilaginous inner tangen-tial wall, indicated by white asterisk, cell lumen indicated by black asterisk. Fig. 26. Connarus conchocarpus (Connaracae),abaxial epidermis. Fig. 27. Geissois biagiana (Cunoniaceae), adaxial epidermis. Fig. 28. Platytheca galioides (Treman-draceae), abaxial epidermis. Fig. 29. Tetratheca thymifolia (Tremandraceae), abaxial epidermis. Figs 30–33. Androeciumdevelopment: Floral buds at an earlier and later stage, sepals removed; from above. Asterisks indicate first stamens todevelop in each episepalous sector. Development proceeds in a lateral and outward direction. Figs 30,31. Geissois pruinosa(Cunoniaceae). Figs 32,33. Vallea stipularis (Elaeocarpaceae). Scale bars = 20 mm in 26–29; 200 mm in 30–33.



naraceae; Fig. 26); Geissois (Fig. 27) and Gillbeea(Cunoniaceae) (cf. also Matthews et al., 2001); andPlatytheca (Fig. 28) and Tetratheca (Tremandraceae)(Fig. 29). The same was found in Anisophyllea andPolygonanthus (Anisophylleaceae; cf. Matthews et al.,2001). Such cells are also present in the carpel epider-mis in Geissois (Cunoniaceae) and Anisophyllea (Anis-ophylleaceae). The presence of such cells is well knownin foliage leaves of several rosid families but, to ourknowledge, not in flowers (among Oxalidales, in Con-naraceae, Cunoniaceae, Elaeocarpaceae, Treman-draceae; Metcalfe & Chalk, 1950; Napp-Zinn, 1973;Gregory, 1998; Matthews et al., 2001; Metcalfe, 1979).

Simple, unicellular, lignified, often tanniferoushairs are present on the sepals in representatives ofall families of Oxalidales. Glandular, multicellularhairs on the dorsal side of the sepals are present inCnestis (Connaraceae), Platydiscus and Acsmithia(only on the pedicel) (Cunoniaceae), and also in Com-bretocarpus (Anisophylleaceae) (see also Matthewset al., 2001; Schönenberger et al., 2001). Stellate hairsare also present on the outside of the sepals of someCunoniaceae (Engler, 1930c) and Tremandraceae(Thorne, 1983); however, it is not certain whether theyare of the same structure.

CorollaThe most striking feature of petals in Oxalidales istheir tendency to be multiply incised or lobed (Fig. 57).This has long been known from some Cunoniaceae(Ceratopetalum; Schizomeria, Fig. 57F,F¢) (Matthewset al., 2001) and Elaeocarpaceae (Aristotelia (onlyslightly), Fig. 56G; Crinodendron, Fig. 57H; Elaeocar-pus, Fig. 57I; Vallea, Fig. 57J). Slight lobulation inConnaraceae (Cnestis), found here, was previouslyunreported (Fig. 57D,D¢). Mostly there are three mainlobes, and often additional secondary ones. Anisophyl-leaceae, which also have lobed petals, most closelyresemble Cunoniaceae, as in both families the petalstend to be small, and in some taxa the petal lobes havethickened ends (Matthews et al., 2001). In addition,petals are absent in many taxa, such as Brunelliaceae,Cephalotaceae, Cunoniaceae (Acsmithia, Geissois,Davidsonia; also many other genera; cf. Engler, 1930c),and Elaeocarpaceae (Sloanea p.p.; Coode, 1983).Clearly, there is a fluctuation between the presence oflobed petals and the absence of petals within families,such as Cunoniaceae, Elaeocarpaceae and Anisophyl-leaceae, and in some cases even within a genus(Ceratopetalum; Hoogland, 1960;1981; Sloanea; Coode,1983; Combretocarpus; Matthews et al. 2001). It wouldbe interesting to know the developmental basis forthis fluctuation. In eudicots, except for Santalales andsympetalous asterids, petals are commonly covered bysepals in bud, they remain small and resume growth

only shortly before anthesis. However, in a number ofOxalidales they become larger than the sepals in budand assume a protective function for the pollina-tion organs, such as in Averrhoa (Oxalidaceae), Con-narus (Connaraceae), Crinodendron (Elaeocarpaceae)(Fig. 87), and in Tetratheca (Tremandraceae)(Fig. 89).

Corolla aestivation is commonly imbricate in Oxal-idaceae and Connaraceae. It is contort in all Oxali-daceae studied. According to Schellenberg (1938)Connaraceae have quincuncial corolla aestivation.However, we found cochlear and quincuncial aestiva-tion in both Connaraceae studied; in a few Con-naraceae petals are involute (Jongkind, 1989). InCunoniaceae (and Anisophylleaceae), aestivation iscommonly open, as petals are small, if present at all(Engler, 1930c; Rozefelds & Pellow, 2000; Matthewset al., 2001). In Elaeocarpaceae aestivation varies, inCrinodendron (see also Bricker, 1991) and Elaeocarpus(see also Venkata Rao, 1953) it is induplicately val-vate, in Vallea cochlear, and in Aristotelia cochlear orquincuncial; this variability is accentuated in Sloanea,in which some species have petals, and these mayhave irregular aestivations with imbricate and val-vate sectors in the same flower (Coode, 1985). InTremandraceae and those Elaeocarpaceae with indu-plicately valvate aestivation, petals are induplicateto such an extent that they enwrap the stamens ofthe same sector (Figs 88,90). In some Cunoniaceae(Ceratopetalum, Schizomeria) and Anisophylleaceae,although the petals are smaller, they also partlyenwrap the stamen(s) of the same sector (Matthewset al., 2001). Petals are commonly free. In Oxalidaceae(Fig. 57A–C) and Connaraceae, however, they arepostgenitally united in the lower zone, except for thevery base, and form a short tube (cf. also Schellenberg,1938; Breteler, 1989); in Sloanea sect. Antholoma theyare united (postgenitally or congenitally?) (Coode,1978; Tirel, 1982).

Petals have a single main vascular bundle andtrace, except for Tremandraceae and some Elaeocar-paceae (Crinodendron, Vallea), which have three mainbundles and traces. In the blade a number of second-ary bundles branch off from the main ones.

Unicellular, commonly lignified hairs are present onthe petals of most taxa studied; they are lacking inTremandraceae, Averrhoa (Oxalidaceae), and Schi-zomeria (but present in Gillbeea among Cunoniaceae).Uniseriate glandular hairs with uni- or multicellularhead are present on the petals of Oxalidaceae (see alsoChin & Phoon, 1982) (Figs 76,77) and Connaraceae(Fig. 78) (hairs unicellular in Oxalis, absent in Cnes-tis). A single, unicellular, capitate hair was found atthe tip of some petals of Platytheca (Tremandraceae).Stomata on petals were only found in Crinodendron(Elaeocarpaceae), possibly because the sepals are



highly reduced and therefore the petals are exposedfrom early on.

AndroeciumThe presence of two stamen whorls in flowers is pre-dominant in rosids and other core eudicots. The twopatterns, diplostemony and obdiplostemony, arevariously present. In diplostemonous flowers, stamenwhorls and the carpel whorl (if isomerous) regularlyalternate. In contrast, in obdiplostemonous flowersthe inner base of episepalous stamens is closer to thefloral centre than that of alternisepalous stamens, andcarpels (if isomerous) are alternisepalous. The devel-opmental conditions for the two patterns were studiedin detail in a range of core eudicots by Eckert (1966),and the systematic distribution was also discussed byRonse Decraene & Smets (1993, 1995, 1998). In Oxal-idales, the presence of two stamen whorls is also com-mon. Flowers are obdiplostemous in Oxalidaceae,Cnestis (Connaraceae), Geissois (Cunoniaceae), Aristo-telia, Crinodendron (Elaeocarpaceae), and Platytheca(Tremandraceae). In Schizomeria (Cunoniaceae) thepattern is not clear, because all stamens are about thesame distance from the floral centre and the gynoe-cium is not isomerous with the other floral whorls. Insome taxa the character is not applicable: (1) becausethere is only one stamen whorl (Connarus, Tetratheca),(2) because petals are lacking (Acsmithia, Brunelli-aceae, Cephalotaceae), or (3) because of polyandry(Sloanea, Vallea). Anisophylleaceae flowers are alsoobdiplostemonous (Tobe & Raven, 1988; Matthewset al., 2001).

Thus, in the Oxalidales studied here there are anumber of obdiplostemonous species, but no diploste-monous ones. In obdiplostemonous flowers, the epipe-talous (alternisepalous) stamens are generally smallerthan the episepalous ones (see also Eckert, 1966). Thisreduction may be variously expressed in length,breadth and thickness of the filaments, in the extremecase these stamens may be sterile or even completelylacking. Among Oxalidales, episepalous stamens arelonger than alternisepalous in Oxalidaceae, Con-naraceae (Cnestis), Brunelliaceae, Cunoniaceae, Ceph-alotaceae, Elaeocarpaceae (Aristotelia, Crinodendron),and Tremandraceae (Platytheca). In such flowers theanthers may be positioned at two levels in bud: theepisepalous above the alternisepalous, whilst inCephalotaceae and Ceratopetalum the reverse is true.Episepalous filaments are thicker in Oxalidaceae,Connaraceae (Cnestis), Brunelliaceae (also broader)and Cunoniaceae (Acsmithia, Schizomeria, both alsobroader). However, alternisepalous filaments (stamin-odes) are broader than episepalous in Averrhoa(Fig. 80), Cnestis, Cephalotaceae (also thicker), andGeissois (also thicker). In polyandrous Elaeocarpaceae

the situation is more complicated (Sloanea, withoutan obvious pattern; Vallea, inner whorl broader andthicker).

A double position of stamens (episepalous or alter-nisepalous) was occasionally found in Brunelliaceae(Cuatrecasas, 1970), Cephalotaceae, and Cunoniaceae(Callicoma, Dickison, 1975b; Davidsonia, Matthewset al., 2001). It is regularly present in Elaeocarpaceae(Aristotelia, Fig. 11; Crinodendron, Fig. 12; Dubouzetia;Peripentadenia) (see also van Heel, 1966; van Balgooy,1976; Bricker, 1991). The case of Tetratheca (Treman-draceae) (Figs 16,51) has puzzled botanists. The twostamens enwrapped by each petal have, probably erro-neously, been interpreted as either an epipetalous andan episepalous stamen of a diplostemonous andro-ecium (van Tieghem, 1906) or a pair of epipetalousstamens in double position (e.g. Thompson, 1976;Suvartha, Satyavathi & Narayana, 1984; Laxmi &Narayana, 1987). From our results, all eight stamensare equidistant from each other and alternate with theeight perianth organs; thus the pairs can be either epi-petalous or episepalous (cf. also Payer, 1857). However,the interpretation of episepalous and not epipetalousdouble positions would correspond with the normalalternation of whorls (see also Saunders, 1939; RonseDecraene & Smets, 1996). In other core eudicots, dou-ble position of stamens, either episepalous or alter-nisepalous, also occurs in some instances (e.g. Eckert,1966; Ronse Decraene & Smets, 1996).

Multiple position of stamens (polyandry) is presentin two families of Oxalidales, Cunoniaceae (Belangera;Geissois, Fig. 9; Eucryphia; Bauera; cf. also Engler,1930a; Dickison, 1975a,b) and Elaeocarpaceae (Sloa-nea, Figs 13,48; Vallea, Fig. 14; also in some generamentioned for double position, stamen number mayfurther increase; Coode, 1987). Eucryphia has up to150 stamens (Forster & Hyland, 1997), Sloanea up tomore than 300 (Tirel, 1982). In polyandrous flowersthe inner stamens tend to be larger than the outerones: among the taxa studied, in Vallea both anthersand filaments are longer, and the filaments arethicker and broader; in Sloanea stamens are longer,although filaments are shorter. In polyandrous Elaeo-carpaceae, stamen development is centrifugal (vanHeel, 1966), in highly polyandrous Cunoniaceae thepattern of stamen initiation is unknown; however, inthe only slightly polyandrous Geissois, it also seems tobe centrifugal (Dickison, 1989; this study). In fact,androecium initiation in Geissois and Vallea is simi-lar: it begins in episepalous sectors and proceeds in alateral and outward direction (this study) (Figs 30–33).

In many eudicots, the stamen filaments remainshort until just before anthesis. However, in mostOxalidales, the filaments are longer than the anthersin bud, such as in Oxalidaceae, Connaraceae, Brunel-



liaceae, Cephalotaceae, and Cunoniaceae. This is alsotrue for Anisophylleaceae. As a consequence, the sta-mens (mainly anthers) tend to be incurved in bud inCephalotaceae and Cunoniaceae (Ceratopetalum, Schi-zomeria, Gillbeea). It also occurs in Anisophylleaceae.This curvature in bud can be so strong in the episepa-lous stamens that they become covered by the epipe-talous ones, such as in Ceratopetalum (Cunoniaceae)(Matthews et al., 2001) and Cephalotaceae. In theextreme, the episepalous filaments may form longloops (Cunonia). Such a curvature is also present inAnisophylleaceae to various degrees, including longloops (Matthews et al., 2001).

Anthers are introrse in all taxa studied, except forthe polyandrous Sloanea where they are irregular(latrorse, extrorse and introrse in the same flower).A connective protrusion is present in Oxalidaceae(Figs 35,36), Connaraceae, Brunelliaceae (Fig. 40),Cephalotaceae (Fig. 41), Cunoniaceae (Ceratopetalum;Schizomeria, Fig. 44), and Elaeocarpaceae (Sloanea).Anthers are commonly dorsifixed; they fluctuatebetween sagittate and x-shaped (within families)(Figs 34–44), and anther dehiscence is of the commoneudicot type (by two longitudinal slits) in most fami-lies. However, in Elaeocarpaceae and Tremandraceaethe anthers are basifixed (Figs 48–51), they are espe-cially long, and they dehisce only apically, by two shortslits or pores in Aristotelia, Sloanea, and Vallea(Fig. 52) (Elaeocarpaceae), or by a single pore (byconfluence over the anther apex) in Crinodendron(Fig. 53) and Elaeocarpus (Elaeocarpaceae) and inTremandraceae (Figs 54,55). This suite of charactersin Elaeocarpaceae/Tremandraceae is apparently cor-related with an adaptation to buzz-pollination and sol-anoid flowers (see below). Restriction of dehiscence totwo apical pores is also present in Bauera (Cunoni-aceae) (Dickison, 1975a). In these poricidal anthersthe endothecium (Fig. 56) is not normally developed inPlatytheca (Fig. 56M) and Tetratheca (Fig. 56N): thealtered endothecium (with thickened outer, not inner,tangential and lateral cell walls) forms a continuousring around the anther. In Elaeocarpaceae the differ-entiation is less pronounced: endothecium cells aremore normally developed, but they are also continuousover the dorsal and ventral side of the anther(Fig. 56J–L).

Stamens have a single vascular bundle and trace inall species studied.

Unicellular lignified hairs are present on the fila-ments in Oxalis, Biophytum, Brunellia (thin-walled),and all Elaeocarpaceae studied. In the latter they arealso present on the anthers (Figs 52,53,91), and inPlatytheca only on the anther (Figs 50,92). Multicellu-lar, uniseriate (slightly moniliform) glandular hairswere found on the filaments in Oxalidaceae and Con-naraceae (Connarus) (Figs 82,83).

GynoeciumIn relatively many Oxalidales (as compared withother rosids), the gynoecium is isomerous with theother organ whorls, such as in Oxalidaceae, manyConnaraceae, Cephalotaceae, Brunelliaceae, fewCunoniaceae (Acsmithia, Aistopetalum, cf. Engler,1930c), Elaeocarpaceae (Vallea, but polyandrous). Inthese cases, the carpels are always in an alternise-palous position, irrespective of whether petals arepresent or absent. This may reflect the general trendof a reduction of the petal sector. In other taxa, car-pel number is lower than organ number in the peri-anth whorls: often two or three, which fluctuateswithin Cunoniaceae, Elaeocarpaceae, and Treman-draceae; a single carpel is only present in severalgenera of Connaraceae (Schellenberg, 1938). Onlyrarely is carpel number higher than sepal and petalnumber, such as in the polyandrous Eucryphia(Cunoniaceae) with four sepals and petals but up to14(-18) carpels (Dickison, 1978), and more excep-tionally in some Connaraceae (our material of Cnes-tis with up to nine carpels; see also Schellenberg,1938). Carpels are free in Connaraceae, and Cephal-otaceae, and almost free in Brunelliaceae andAcsmithia (Cunoniaceae) (cf. also Cuatrecasas, 1970;Hoogland, 1979, 1987), and exceptionally in Oxali-daceae: Oxalis aberrans (Knuth, 1930). In other taxathey are united to various degrees. The ovaries aresuperior in most taxa. However, in Cunoniaceae,they are slightly inferior to semi-inferior (Ceratopeta-lum, Schizomeria, Geissois; Dickison, 1975b; Mat-thews et al., 2001), to almost completely inferior inspecies of Bauera (Dickison, 1975a), in Ceratopeta-lum and Pullea (Engler, 1930c; Dickison, 1975b), andvery slightly inferior in Aristotelia and Vallea (Elaeo-carpaceae). They are inferior in Anisophylleaceae(Tobe & Raven, 1988; Matthews et al., 2001). A dis-tinct vertical rib on the dorsal ovary wall is presentin Averrhoa (Oxalidaceae), Cnestis (Connaraceae),Gillbeea (Cunoniaceae), and Crinodendron (Elaeocar-paceae). In floral buds of Brunelliaceae andAcsmithia (Cunoniaceae) the styles are incurved(Figs 58,59).

Except for Cephalotaceae with completely plicatecarpels, the carpels (gynoecia) are ascidiate (syn-ascidiate) to various degrees. In Oxalidaceae,Brunelliaceae, Cunoniaceae, Elaeocarpaceae andTremandraceae the ovaries are ascidiate or synascid-iate for at least half of their length. In Connaraceae,the ascidiate zone is shorter. In most cases the pla-centa is situated in the transition zone betweenascidiate (synascidiate) and plicate (symplicate). Theplacenta is completely in the synascidiate zone inAverrhoa (Oxalidaceae), Schizomeria (Cunoniaceae),Crinodendron (Elaeocarpaceae), and Platytheca(Tremandraceae).



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Figures 45–55. Figs 45–47. Pendant flowers. Figs 45,46. Elaeocarpaceae. Fig. 45. Crinodendron hookerianum. Fig. 46.Elaeocarpus reticulata (Photo: Bálint Berg). Fig. 47. Tetratheca thymifolia (Tremandraceae). Figs 48–51. Floral buds,sepals and petals removed; episepalous view. Extent of filament indicated by pair of arrowheads. Figs 48,49. Elaeocar-paceae. Fig. 48. Sloanea macbrydei. Fig. 49. Crinodendron patagua. Figs 50,51. Tremandraceae. Fig. 50. Platytheca galio-ides. Unicellular, tanniferous hairs with a multicellular pedestal indicated by arrow. Fig. 51. Tetratheca thymifolia. Figs 52–55. Anthers at anthesis. Figs 52,53. Elaeocarpaceae. Fig. 52. Vallea stipularis. Dehiscence restricted to apex of theca(arrowheads indicate extent of opening; arrow indicates closed part of stomium) Fig. 53. Crinodendron patagua. Apicalpore of anther. Figs 53,54. Tremandraceae. Apical pore of anther. Fig. 54. Platytheca galioides. Fig. 55. Tetratheca thymi-folia. Scale bars = 1 mm in 48–51; 300 µm in 52, 53; 100 µm in 54, 55.



A ventral slit is present in the plicate and sympli-cate zones of the gynoecium. In most taxa, it extendsup to the stigma. However, it ceases farther down, andthe uppermost part of the style is solid in Cephalota-ceae and Crinodendron (Elaeocarpaceae). Both condi-tions also occur in Anisophylleaceae (Matthews et al.,2001). Especially interesting, because not so common,are cases in which the ventral slit tapers downwardsas an external furrow in ascidiate ovaries, such as inConnaraceae (Figs 4,5,60,61) (see also Leinfellner,1969, 1970), Brunelliaceae (Figs 6,62), and Acsmithia(Cunoniaceae) (Fig. 8). This feature is also common inLeguminosae (Leinfellner, 1969, 1970) and was one of

the supporting characters for the former association ofConnaraceae and Leguminosae.

The taxa studied generally have angiospermy type 3(as defined by Endress & Igersheim, 2000), i.e. anunfused, secretion-filled stylar canal, but with no con-nection to the outside. Exceptions are Cephalotaceae(type 4, without a stylar canal) and Platytheca (type 2,stylar canal connected with the outside in the stigma);Acsmithia is uncertain, because only pre- andpostanthetic material was available. Dickison (1971)mentioned the presence of open carpel sutures at thelevel of placentation in some Connaraceae and Eyde(1970) found the same in Brunelliaceae. This is prob-

Figure 56. TS anthers showing extent of endothecium and endothecium-like tissue (shaded). A–C, Oxalidaceae. A, Oxalisortgiesii. B, Biophytum dendroides. C, Averrhoa carambola. D,E, Connaraceae. D, Cnestis ferruginea. E, Connarus conchocarpus.F, Cephalotaceae; Cephalotus follicularis. G–I, Cunoniaceae. G, Acsmithia davidsonii. H, Geissois biagiana. I, Schizomeriawhitei. J–L, Elaeocarpaceae. J, Crinodendron patagua. K,L, Sloanea macbrydei. K, upper region of anther directly belowconnective protrusion. L, middle region. M,N. Tremandraceae. M, Platytheca galioides. N, Tetratheca thymifolia. Scalebar = 400 µm.

M

L

HGFE

DCBA

N

KI J



Figure 57. Petals from ventral side, in A–C all five petals drawn, in D–L only one petal drawn. A–C, Oxalidaceae. Petalspostgenitally united (dotted lines). A, Oxalis ortgiesii. B, Biophytum dendroides. C, Averrhoa carambola. D,E, Connaraceae.D, Cnestis ferruginea. E, Connarus conchocarpus. F, Schizomeria whitei (Cunoniaceae). G–J, Elaeocarpaceae. G, Arisoteliachilensis. H, Crinodendron patagua. I, Elaeocarpus cf. subvillosus. J, Vallea stipularis. K,L, Tremandraceae. K, Platythecagalioides. L, Tetratheca thymifolia. D¢,F¢, higher magnification of D,F. Scale bars = 5 mm in A–L; 2 mm in D¢,F¢.

IHGF

EDCBA

LKJ

D´

F´

ably an artefact because they studied herbariummaterial. In our liquid-fixed material the carpels werenot open.

Stigmas are often punctiform; this is the case forindividual carpels in many Cunoniaceae, and is aneven more prominent feature, due to the union of thepunctiform stigmas of all carpels of a flower into onepoint, in most Elaeocarpaceae and in Tremandraceae(Figs 93,94). In the latter two this seems to be func-tionally related to the buzz-pollinating mechanism(see e.g. Endress, 1994). Decurrent stigmas arepresent in some Oxalidaceae (Figs 84,85), Con-naraceae (Fig. 86), in Brunelliaceae, Cephalotaceae,Vesselowskya (Cunoniaceae) and Aristotelia (Elaeocar-paceae) (see also Dickison, 1989). In some Cunoni-aceae (Acsmithia) and Elaeocarpaceae (Vallea) theyare slightly capitate. Stigmas are commonly unicellu-lar, papillate. Only in Oxalis, Averrhoa, and Connaruswere massive, multicellular protuberances without

conspicuous unicellular papillae found (Figs 84–86).Stigmas are secretory in all taxa, in which we studiedanthetic flowers (Vallea though unclear).

A stylar canal is present in all families of Oxal-idales, except for Cephalotaceae. It is also present inAnisophylleaceae (Matthews et al., 2001). This canalis filled or lined with secretion at anthesis. PTTT ispresent as a single cell layer accompanying theventral slit. Only in Oxalidaceae (Oxalis, Averrhoa),Connaraceae (Cnestis), and Elaeocarpaceae (Crinoden-dron, Sloanea, Vallea) it may encompass more thanone cell layer. PTTT of all carpels is commonly conflu-ent in the symplicate zone in the taxa with syncarpousgynoecia (not in Sloanea), thus seemingly forming acompitum. However, it was not experimentally testedwhether this zone functions as a compitum. In thestyle of some taxa a gap is present between the con-tiguous, free or postgenitally or congenitally unitedcarpels, which is, in some cases, also lined with PTTT.



Figures 58–64. Figs 58,59. Floral buds with incurved styles, sepals removed; from above. Fig. 58. Brunellia standleyana(Brunelliaceae). Fig. 59. Acsmithia davidsonii (Cunoniaceae). Figs 60–62. TS ascidiate zone of ovary with external ventralfurrow (arrow) and ventral vascular bundle between ovules (arrowhead). Figs 60,61. Connaraceae. Fig. 60. Cnestis ferrug-inea. Fig. 61. Connarus conchocarpus. Fig. 62. Brunellia standleyana (Brunelliaceae). Figs 63,64. Cog-wheel-shapednectary disc with unicellular, tanniferous hairs (arrow). Fig. 63. Geissois biagiana (Cunoniaceae). Fig. 64. Crinodendronpatagua (Elaeocarpaceae). Scale bars = 400 mm in 58,59; 100 mm in 60–62; 300 mm in 63,64.



However, it is not certain whether it forms part of acompitum. Such a gap was found in Oxalidaceae,Brunelliaceae, Cunoniaceae, Elaeocarpaceae, andTremandraceae.

Placentation is always axile, irrespective of whetherthe placenta is in the synascidiate or symplicate zone.It is near the base of the locules in Connaraceae andCephalotaceae. The description of Tetratheca by vanTieghem (1906) as having parietal placentae does notapply, as the ovary is synascidiate. The ovary locule isfilled with secretion in Brunelliaceae (but mainly justaround region of funicle), Cephalotaceae, and someCunoniaceae (Gillbeea, Davidsonia, Geissois).

The carpels commonly have a dorsal (extending upto the stigma) and two (somewhat shorter) lateralvascular bundles. However, in some taxa the dorsalbundle is only weakly developed or absent, such as inBiophytum and Oxalis (Oxalidaceae), Aristotelia (Elae-ocarpaceae), and Platytheca (Tremandraceae). Therudimentary dorsal bundle is in the plane, in whichlater the fruit dehisces (except for Aristotelia, whichhas indehiscent fruits). A number of secondary lateralbundles may be present and form a network with thedorsal and the primary lateral bundles. In the groupswith united ovaries, synlateral bundles are formedbetween adjacent carpels in Oxalidaceae, Cunoni-aceae, Elaeocarpaceae, and Tremandraceae; two setsof synlaterals in radial arrangement are present inOxalidaceae (see also, Saunders, 1928; Sauer, 1933;Dave et al., 1975).

The carpels and/or the floral centre between the car-pels are commonly covered with unicellular lignifiedhairs in all families of Oxalidales (see also Knuth,1930, 1931; Schellenberg, 1938). Unicellular hairswithin ovary locules were found in Oxalis (Oxali-daceae) (see also Sauer, 1933), Crinodendron (alsomulticellular glandular hairs) (Fig. 95) and Vallea(Elaeocarpaceae), and in Tetratheca (Tremandraceae)(Fig. 96); Dickison (1971) also mentions hairs in youngfruits of Connarus (Connaraceae).

OvulesTwo or slightly more ovules per carpel are most com-mon in Oxalidales. A single ovule was only found inCephalotaceae and in Platytheca (Tremandraceae). Alarge number of ovules are never present, but morethan 15 were found in Geissois (Cunoniaceae) andCrinodendron (Elaeocarpaceae). Higher numbers areknown from Weinmannia (Cunoniaceae) and from Pla-tydiscus, a Cretaceous, probably cunoniaceous fossil(Schönenberger et al., 2001). Ovule position is alwayslateral, even if they are in the (syn)ascidiate zone(except, perhaps, in the studied Oxalis, if three ovulesare present). If two ovules are present, they are eithercollateral (Connaraceae, Brunelliaceae) or alternating(Oxalis, Aristotelia, Vallea, Tetratheca). If more ovules

are present, they may also be collateral in pairs(Cunoniaceae, Sloanea, Tetratheca p.p., for the latter,cf. Thompson, 1976) or alternating (Oxalidaceae), andthe placenta is in two lines (only in Crinodendron, witha higher ovule number, we found two to three lines)(Fig. 65). The ovules commonly direct their micropyleupwards, but downwards in Cephalotaceae and Geis-sois (Cunoniaceae). In Aristotelia and Vallea (Elaeocar-paceae), of the two ovules one is directed upwards andthe other downwards. In collateral ovules of Con-naraceae and Brunelliaceae, the funicles appear to besomewhat united in the (syn)ascidiate zone, or, inother words, the placenta forms a ridge (Figs 60–62).

Crassinucellar, bitegmic, anatropous ovules aremost certainly plesiomorphic in core eudicots. Theyare shared by most taxa of Oxalidales; earlier studies:Oxalidaceae (Thathachar, 1942; Herr, 1974; Govil& Kaur, 1989; Boesewinkel, 1997), Connaraceae(Mauritzon, 1939), Brunelliaceae (rudimentary,Lopez-Naranjo & Huber, 1971), Cephalotaceae (rudi-mentary, Schweiger, 1909), Cunoniaceae (Mauritzon,1933, 1939; Govil & Saxena, 1976; Prakash &McAlister, 1977; Kennedy & Prakash, 1981), Elaeo-carpaceae (Mauritzon, 1934a; Venkata Rao, 1953), andTremandraceae (Boesewinkel, 1999). It is, however,noteworthy that ovules in some Oxalidales areonly hemianatropous (Biophytum, Cnestis, Schizome-ria, Ceratopetalum; for the latter two see also Maurit-zon, 1939; Aristotelia, Mauritzon, 1934a) or almostorthotropous (Connarus, see also Schellenberg, 1938;Mauritzon, 1939). In addition, in some Oxalidalesovules have a thin nucellus (Averrhoa, cf. alsoBoesewinkel, 1985; Platytheca) or are only weaklycrassinucellar (Cephalotaceae) or even (incompletely)tenuinucellar (sensu Endress, 2002) (Oxalis;Hammond, 1908; Mauritzon, 1934b; Herr & Dowd,1968; Narayana, 1970; Bouman, 1974; Vereshchagina,1985; Biophytum; Mauritzon, 1934b; Thathachar,1942; Boesewinkel, 1985).

The thin nucelli (see above), which are commonlydissolved at maturity are associated with an endothe-lium (integumentary tapetum) in the epidermis of theinner integument that is contiguous with the nucellus.This was found here and/or was described in the liter-ature for Oxalidaceae (Oxalis, see also Narayana,1970; Biophytum, Thathachar, 1942; Averrhoa,Boesewinkel, 1985; Dahlgren, 1988), Connaraceae(Connarus; see also Mauritzon, 1939), Cunoniaceae(Bauera, Mauritzon, 1939), Elaeocarpaceae (Elaeocar-pus, Venkata Rao, 1953; Dahlgren, 1988; Sloanea(weak); Crinodendron; Vallea; not found in Aristoteliachilensis, but reported by Mauritzon, 1934a, fortwo other Aristotelia species), and Tremandraceae(Platytheca; Tetratheca, cf. Boesewinkel, 1999). Posta-ment formation in the mature nucellus was reportedfor Cunoniaceae (Callicoma, Kennedy & Prakash,



Figure 65. Placentae with ovules. Each composite figure shows arrangement of ovules (figure on left) and attachmentpoints of ovules (figure on right). The dotted line demarks the region of the inner part of the ventral slit as it appears inthis view (the ventral slit extends into the ascidiate zone as a furrow), and the solid line connects ovules positioned onthe same side of the placenta. A–C, Oxalidaceae. A, Oxalis ortgiesii. B, Biophytum dendroides. C, Averrhoa carambola. D–F,Cunoniaceae. D, Acsmithia davidsonii. E, Geissois biagiana. F, Schizomeria whitei. G,H, Eleaocarpaceae. G, Crinodendronpatagua. H, Sloanea macbrydei. A–C, E–G are from an open flower, D, from a bud, H, from an opening bud. Scalebar = 500 mm.

DCBA

F

E

HG

1981; Ceratopetalum, Mauritzon, 1939), Elaeocar-paceae (Elaeocarpus, Venkata Rao, 1953; Dahlgren,1988), and Tremandraceae (Tetratheca, Boesewinkel,1999).

The micropyle is commonly formed by both integ-uments. It is formed by the inner integument inConnarus, Cephalotaceae, and Sloanea; by both integ-uments or the inner integument in Geissois, Aristote-lia, and Crinodendron (ovules were not mature in ourmaterial of Cnestis and Acsmithia). If it is formed byboth integuments, the entrance into the micropyle, i.e.the outer integument, mostly appears as a longitudi-nal slit (Averrhoa, Biophytum, Cephalotaceae, Cunon-iaceae, cf. Matthews et al., 2001; Crinodendron,Elaeocarpus, Tetratheca; for Tremandra, cf. Payer,1857) (Figs 66–69). This is also the case in Anisophyl-leaceae (Matthews et al., 2001). If the micropyle isformed by the inner integument, the closure is moreirregular. In Brunelliaceae and Tremandraceae(Tetratheca, Boesewinkel, 1999; Platytheca) the outerintegument forms a funnel-like structure around anobturator (Figs 70,71,73); in Oxalis it forms a funnel-like structure around the chalaza of the adjacentupper ovule (Fig. 72). In more deviating cases, the

micropyle was not completely closed. Zig-zag micro-pyles were found scattered in different families:Oxalidaceae (Averrhoa), Cunoniaceae (Schizomeria),Elaeocarpaceae (Crinodendron; Aristotelia, Mauritzon;1934a; Elaeocarpus, Venkata Rao, 1953), and Treman-draceae (Tetratheca, Boesewinkel, 1999). Both integu-ments are lobed in Oxalis, Connarus, Brunelliaceae,Elaeocarpaceae, and Tremandraceae; only outerinteguments were found to be lobed in Averrhoa; bothinteguments are unlobed in Cephalotaceae andCunoniaceae.

Whereas in Oxalidaceae and Connaraceae the innerand outer integuments are of about of the same thick-ness, the inner integument is considerably thickerthan the outer in Brunelliaceae, Cephalotaceae,Cunoniaceae, Elaeocarpaceae and Tremandraceae.The thickest inner integuments were found in Aristo-telia (7–10 cell layers) and Platytheca (9–12 cell layers)(Fig. 73).

Ovules with a chalazal appendage are present inOxalis (Oxalidaceae) (Fig. 72), Aristotelia (Fig. 99) andVallea (Elaeocarpaceae), and Tetratheca (Treman-draceae) (Fig. 102). The appendage differentiates asan elaiosome in seeds of Tetratheca and Tremandra



Figures 66–73. Figs 66–69. Ovules at anthesis. Micropyle formed by a longitudinal slit of the outer integument (arrow-heads indicate extent of slit; asterisk indicates attachment region of ovule). Fig. 66. Averrhoa carambola (Oxalidaceae).Fig. 67. Schizomeria whitei (Cunoniaceae). Fig. 68. Elaeocarpus cf. subvillosus (Elaeocarpaceae). Fig. 69. Tetratheca ciliata(Tremandraceae). Figs 70–73. Ovules at anthesis with a lobed, funnel-like outer integument (arrow). Fig. 70. Brunelliastandleyana (Brunelliaceae), from the side. Fig. 71. Platytheca galioides (Tremandraceae), from the side. Figs 72,73. LSovule. Fig. 72. Oxalis ortgiesii (Oxalidaceae). Nucellus and inner integument elevated on a stalk (arrowhead); chalazalappendage (asterisk). Fig. 73. Platytheca galioides (Tremandraceae); obturator indicated by arrowhead. Scale bars = 50 mmin 66,70,71; 100 mm in 67–69,72,73.



Figures 74–81. Figs 74,75. TS floral bud, showing hooked, postgenitally connected petals (extent of connection indicatedby arrowheads). Fig. 1. Averrhoa carambola (Oxalidaceae). Fig. 75. Connarus conchocarpus (Connaraceae). Petal tipsmeristematic or secretory (arrow). Figs 76–78. Petals with multicellular, glandular hairs. Figs 76,77. Oxalidaceae. Fig. 76.Biophytum dendroides. Fig. 77. Averrhoa carambola. Fig. 78. Connarus conchocarpus (Connaraceae). Figs 79–81. Floralbuds, epipetalous view, sepals and petals removed, showing staminal tube (extent of staminal tube indicated by arrow-heads), staminodes (arrow) and nectaries. Figs 79,80. Oxalidaceae. Fig. 79. Oxalis ortgiesii.Fig. 80. Averrhoa carambola.Fig. 81. Connarus conchocarpus (Connaraceae) (this bud with a single epipetalous staminode). Scale bars = 100 mm in 74;50 mm in 75; 150 mm in 76–78; 1 mm in 79–81.



(Tremandraceae) (Berg, 1975; Boesewinkel, 1999).Arils are present in seeds of many Connaraceae(Schellenberg, 1938; Corner, 1976; Breteler, 1989),Dapania (Oxalidaceae) (Corner, 1976), and Sloanea(Elaeocarpaceae) (Coode, 1983).

The vascular bundle of the ovule extends to the cha-laza in all species studied here. There are no branchesextending into the integuments at anthesis. In seedsthe vascular system may be more extensive (Davidso-nia, Cunoniaceae; Doweld, 1998).

The surface of the ovule is tanniferous inOxalidaceae (Biophytum, Averrhoa), Connaraceae(Connarus), and Cunoniaceae (Acsmithia, Geissois,

Schizomeria). The inner epidermis of the inner integ-ument is tanniferous in Connaraceae (Connarus),Cephalotaceae, and Cunoniaceae (Geissois, Schizome-ria). Boesewinkel (1999: 776) emphasizes that theendotesta in Platytheca is remarkably similar to thatof Oxalidaceae, because it can be artificially split intotwo layers, in a similar way as the endotesta naturallysplits into two parts for the seed ejection mechanismin Oxalis and Biophytum.

Unicellular hairs on ovules are present inElaeocarpus (Elaeocarpaceae) (Figs 97,98) andPlatytheca (Tremandraceae) (for Platytheca, see alsoBoesewinkel, 1999) (Figs 100,101). Interestingly, the

Figures 82–86. Figs 82,83. Stamen filaments with multicellular glandular hairs (arrowhead). Fig. 82. Oxalis ortgiesii(Oxalidaceae). Unicellular hairs with warty ornamentation (arrow) also present. Fig. 83. Connarus conchocarpus (Con-naraceae). Figs 84–86. Stigma from ventral side. Multicellular, glandular hairs indicated by arrow. Figs 84,85. Oxalidaceae.Fig. 84. Oxalis ortgiesii. Fig. 85. Averrhoa carambola. Fig. 86. Connarus conchocarpus (Connaraceae). Scale bars = 50 mmin 82,83; 150 mm in 84–86.



seeds in Elaeocarpus are not hairy, as they areenclosed in a thick endocarp (Tirel, 1978; Coode, 1983;Zmarzty, 2001); however, in Elaeocarpaceae, hairs arepresent on seeds of Dubouzetia australiensis (Coode,1987). In Tetratheca and Tremandra (Tremandraceae)seeds are pilose (Netolitzki, 1926; Thompson, 1976).Hairs are also present on seeds in Acrophyllum, Cald-cluvia and Weinmannia (Cunoniaceae) (Engler, 1930c;Dickison, 1984; Webb & Simpson, 1991).

NectariesNectaries are present in most Oxalidales, but notablyabsent in some Elaeocarpaceae (Sloanea) and Trem-andraceae, which have specialized pollen flowers.Commonly the nectaries are discs around the gyno-ecium base, which protrude as lobes between stamenfilaments, such as in Brunelliaceae, Cephalotaceae,Cunoniaceae (Ceratopetalum; Schizomeria; Acsmithia;Geissois, Fig. 63), Elaeocarpaceae (Aristotelia; Crino-dendron, Fig. 64; Vallea). Such nectaries are alsopresent in Anisophylleaceae (Anisophyllea). In Oxali-daceae, nectaries are located at the base of the epipe-talous stamen/staminode filaments (and nectar isavailable for pollinators through a channel formed byeach petal claw). In Connaraceae the nectaries arealso at the base of the stamens.

The nectaries in most Oxalidales are of the meso-phyll type (in the terminology of Vogel, 1977), in whichnectar is secreted from layers below the epidermis andreleased from intercellular spaces through stomata-like pores. Stomata were found on the nectaries ofmost taxa, except for Biophytum (Oxalidaceae), David-sonia (Cunoniaceae) (Matthews et al., 2001), Aristote-lia and Vallea (Elaeocarpaceae). In many of these taxawith nectaries, the epidermis is distinct from thesecretory tissue, either vacuolate or tanniferous.Nectaries with hairs were found in Brunelliaceae,Davidsonia and Geissois (Cunoniaceae) (Fig. 63), andElaeocarpus p.p. (Coode, 1984), and Crinodendron(Elaeocarpaceae) (Fig. 64). They are also known fromCombretocarpus (Anisophylleaceae) (Matthews et al.,2001). In some, but not all taxa the nectaries areserved by numerous vascular bundles, which aremainly phloic.

FLORAL STRUCTURE AND SYSTEMATICS

Oxalidales in generalThe seven families currently composing the Oxal-idales (Figs 103, 104) were systematically widelyseparate before their congregation by comparativemolecular studies, which encompassed a large numberof core eudicots (APG, 1998). In Soltis et al. (2000),based on a combined multigene analysis using 18S,rbcL and atpB, Oxalidaceae are sister to a clade

composed of Cunoniaceae sister to Elaeocarpaceae(with Tremandraceae nested in them). In Savolainenet al. (2000), based on rbcL alone, but containingmore families, the topology is: (Oxalidaceae+ Connaraceae) + (Brunelliaceae + (Elaeocarpaceae,including Tremandraceae, + (Cephalotaceae + Cunon-iaceae))), most of these clades with high or mediumbootstrap support. The most surprising of these newrelationships are Oxalidaceae and Connaraceae as sis-ters, and Tremandraceae nested in Elaeocarpaceae.

However, somerelationships within Oxalidales havelong been recognized. Brunelliaceae, sometimes alsoCephalotaceae, were often associated with Cunoni-aceae (Engler, 1930a); they were accommodated inRosales or in smaller orders split from Rosales, thustogether with a number of other families that are cur-rently not in Oxalidales. Van Tieghem (1901, 1906)included Tremandraceae in his Oxalidales because ofsimilarities in ovule structure. However, among the 24families of his Oxalidales there are no other families ofthe order in its present circumscription. Engler’s(1931) Geraniales contained 21 families, among themOxalidaceae and Tremandraceae (the other families ofEngler’s Geraniales are currently in Saxifragales,Fabales, Geraniales, Capparales, Malpighiales, Sapin-dales, Myrtales, unplaced rosids, and Lamiales, in thesense of APG, 1998). Also Bauera (Cunoniaceae) andTremandraceae were once brought together (Hallier,1901). Mauritzon (1939) found similarities betweenCunoniaceae and Connaraceae in placenta and ovulestructure.

In more recent non-molecular classifications, Con-naraceae were placed in Rosales (Cronquist, 1981:between Brunelliaceae and Eucryphiaceae (Cunoni-aceae)), or in Fabineae (Rutanae, Dilleniidae; Thorne,2000). Oxalidaceae were in Geraniales (Cronquist,1981; Thorne, 2000), or in their own order, Con-narales, between Sabiales and Rutales (Takhtajan,1997). Tremandraceae have been viewed to be relatedto Polygalales (Cronquist, 1981; Takhtajan, 1987),Malpighiales (close to Polygalales) (Takhtajan, 1997)or to Pittosporales (Carlquist, 1977; Thorne, 1983).Thorne (1983) mentions Tremandraceae and somePittosporaceae to have poricidal anthers. Indeed, thisand the shared ‘solanoid’ floral architecture, whichis evolutionarily shaped by buzz-pollination (cf. e.g.Vogel, 1978; Endress, 1994), gives a suggestive super-ficial similarity of the flowers in the two families. It is,however, interesting that the same traits are alsoshared between Tremandraceae and Elaeocarpaceae(see below). Thorne (2000) placed both Oxalidaceaeand Tremandraceae in his Geraniales. Boesewinkel(1999: 780) found that the ovules and seeds of Trem-andraceae resemble those of Oxalidaceae, specificallytheir ‘elongated nucellus, the multiplicative innerintegument, their crystalliferous endotesta and a



Figures 87–94. Figs 87–90. Floral buds. Figs 87,89. Floral buds; episepalous view. Figs 88,90. Petal surrounding groupof stamens (arrowhead) in bud; ventral side. Figs 87,88. Crinodendron patagua (Elaeocarpaceae). Figs 89,90. Tetrathecathymifolia (Tremandraceae). Figs 91,92. Anther with unicellular, lignified hairs (arrow); ventral side. Fig. 91. Valleastipularis (Elaeocarpaceae). Fig. 92. Platytheca galioides (Tremandraceae). Figs 93,94. Stigmas of all carpels united intoa single point (arrow). Fig. 93. Crinodendron patagua (Elaeocarpaceae), anthesis. Fig. 94. Tetratheca thymifolia (Treman-draceae), preanthesis. Scale bars = 1 mm in 87, 89, 90; 2 mm in 88; 200 mm in 91, 92; 75 mm in 93, 94.



Figures 95–102. Figs 95,96. Ovary locule with lignified hairs (arrow). Fig. 95. Crinodendron patagua (Elaeocarpaceae).Fig. 96. Tetratheca ciliata (Tremandraceae), ovules removed (arrowhead indicates attachment point of removed ovule).Figs 97–102. Ovules at anthesis. Figs 97,100. Ovule with hairs (arrow). Figs 98,101. ovule hairs (arrow), in highermagnification. Figs 99,102. Ovule with chalazal appendage (arrow). Figs 97–99. Elaeocarpaceae. Figs 97,98. Elaeocarpuscf. subvillosus. Fig. 99. Aristotelia chilensis. Lobed inner integument forming micropyle (arrowhead). Figs 100–102.Tremandraceae. Figs 100,101. Platytheca galioides. Fig. 102. Tetratheca ciliata. Micropyle indicated by arrowhead;point of attachment of ovule indicated by asterisk. Scale bars = 200 mm in 95–97, 99, 102; 100 mm in 98, 101; 400 mmin 100.



fibrous exotegmen. In Oxalis and Biophytum, duringactive seed dispersal, the crystalliferous endotesta issplit in a way similar to the artificial splitting of theseed coat of Tremandraceae (Boesewinkel, 1985)’.Elaeocarpaceae are in Violanae, Dilleniidae (Thorne,2000).

Neither the family pair Oxalidaceae and Con-naraceae, nor Elaeocarpaceae and Tremandraceaewere in close proximity in more recent precladis-tic morphological classifications (Takhtajan, 1959,though, mentioned a possible affinity of Connaraceaewith Geraniales). However, Connaraceae and Gerani-ales (including Oxalidaceae) appeared as sisters in thenon-DNA cladistic analysis of rosids by Hufford(1992), and Oxalidaceae and Connaraceae appearedas sisters in the non-DNA analysis of angiosperms byNandi et al. (1998).

Numerous fossils of Oxalidales, including reproduc-tive structures, have been recovered, especially ofCunoniaceae and Elaeocarpaceae. They are mainlyfrom the early to mid-Tertiary, and not from the crit-

ical Cretaceous period, in which the families divergedfrom each other (Cunoniaceae: Hill, 1991; Holmes &Holmes, 1992; Carpenter & Buchanan, 1993; Pole,1993; Taylor & Hill, 1996; Barnes & Hill, 1999a,b;Barnes & Jordan, 2000; Barnes, Hill & Bradford,2001; Poole, Hunt & Cantrill, 2001; Elaeocarpaceae:Rozefelds & Christophel, 1996a,b). Thus they maygive information on the evolution within these fami-lies, but give less information about the interfamilialrelationships. An exception is Upper Cretaceous fossilflowers, which have traits of Cunoniaceae and Aniso-phylleaceae (currently in Cucurbitales, Schwarzbach& Ricklefs, 2000; Soltis et al., 2000), and which maysupport relationships between these two families(Matthews et al., 2001; Schönenberger et al., 2001).

Families of OxalidalesFeatures restricted to single families of Oxalidalesrepresent potential autapomorphies for these families.However, as long as the basal core eudicots are notequally studied and the phylogenetic relationshipsbetween the orders are not resolved this remainsunclear, especially if such features also occur in fami-lies of related orders.

In Oxalidaceae, the sepal mesophyll is especiallylarge-celled (Oxalis, Averrhoa, and to a lesser degreein Biophytum). Petal aestivation is contort (but seebelow). Anthers have stomata on the dorsal side of theconnective; they were not found in other families ofOxalidales, but are known from other rosids, espe-cially some Geraniales, Fabales, Sapindales, and Mal-pighiales (Endress & Stumpf, 1991). Carpel synlateralvascular bundles are present in more than one set ineach septum. Ovules are incompletely tenuinucellar(Oxalis, Biophytum). In Connaraceae, ovules are oftenalmost orthotropous (Schellenberg, 1938; Mauritzon,1939). In Brunelliaceae tanniferous tissue is absent inflowers (except for the unicellular hairs). Brunelliawas sometimes included in Cunoniaceae but appearsnow as a separate family (Orozco, 1997; Savolainenet al., 2000). In Cephalotaceae, flowers exhibit severalprobable autapomorphies. They are constantly 6-merous. The connective protrusion is a thick knob oflarge cells (pseudonectary?). Carpels are completelyplicate. Angiospermy is of type 4 (as there is no stylarcanal). A single downward-directed ovule is presentper carpel. Nectaries have unusual, long protrusions.Oxalate crystals or druses were not found (but also inAcsmithia of Cunoniaceae). Elaborated pitcher leavesand carnivory are a striking autapomorphy in the veg-etative region (Ehler, Schill & Barthlott, 1973; Adams& Smith, 1977; Froebe & Baur, 1988). Cunoniaceaeare diverse in floral structure, and we did not find sin-gle traits as special autapomorphies. The proposedinclusion of Bauera (Bensel & Palser, 1975; Prakash &McAlister, 1977), Davidsonia (Moody & Hufford, 2000;

Figures 103 –104. Fig. 103. Cladogram of rosids (simpli-fied after Soltis et al., 2000; fig. 1A). Fig. 104. Cladogram ofOxalidales (simplified after Savolainen et al., 2000; fig. 3).

Oxalidaceae

Connaraceae

Brunelliaceae

Cephalotaceae

Cunoniaceae

Elaeocarpaceae(Including Tremandraceae)

Malpighiales

Oxalidales

Celastrales

Zygophyllales

Fabales

RosalesCucurbitales

Fagales

Eurosid II

CrossosomatalesMyrtales

Geraniales

103

104



Matthews et al., 2001), and Eucryphia (Hideux &Ferguson, 1976) was supported by molecular and mor-phological studies (Soltis & Soltis, 1997; Bradford &Barnes, 2001), that of Bauera and Eucryphia, also ear-lier by non-DNA studies (Hufford & Dickison, 1992).In Elaeocarpaceae anthers have lignified hairs with abroad base (Aristotelia, Crinodendron). Stamens aremore than double the number of the floral merism(except for some Sericolea species, van Balgooy, 1982).Androecia with a larger stamen number are commonin the family (also a few Cunoniaceae are polyandrousbut not in the basal clade) (Bradford & Barnes, 2001).The close relationship between Aristotelia and Vallea(Coode, 1985) is supported by our study. Treman-draceae have highly specialized anthers with a singleterminal pore at the end of a snorkel-like extension.

Oxalidaceae and ConnaraceaeAccording to results from analyses of molecularsequence data (Savolainen et al., 2000), Oxalidaceaeand Connaraceae, Cephalotaceae and Cunoniaceae,Elaeocarpaceae and Tremandraceae, form threeclades (Fig. 104). Tremandraceae are nested in Elaeo-carpaceae, whereas the families of the former twopairs are sisters to each other. Can these new relation-ships be supported on the basis of morphologicalresults? What are the potential synapomorphies in flo-ral structure for these clades within Oxalidales?

Oxalidaceae and Connaraceae share some featuresthat are unique for Oxalidales, and some of them areeven rare in eudicots. In both families, dimorphic andtrimorphic heterostyly is present (for Oxalidaceae:e.g. Hildebrand, 1867; Darwin, 1877; Mulcahy, 1964;Ornduff, 1964; Weller, 1981, 1992; Lack & Kevan,1987; Richards & Barrett, 1992; Shibaike et al., 1995;Trognitz & Hermann, 2001; for Connaraceae: Burck,1886; Schellenberg, 1938; Baker, 1962; Lemmens,1989). The sharing of trimorphic heterostyly is espe-cially significant, as it is otherwise known from onlyvery few angiosperm families. Petals are postgenitallyunited into a tube near the base but free directly at theinsertion zone (Oxalidaceae, Figs 1H–J,2B–J,3G–J,57A–C; Connaraceae, Figs 4D–H,5B–E) (for Oxali-daceae, see also Hartl, 1957; for Connaraceae, see alsoSchellenberg, 1938); in addition, the postgenitallyunited areas are not symmetrical but, as an expres-sion of the imbricate aestivation in the distal part ofthe corolla, they appear hooked together in transversesections (Figs 74,75). Both families share similar mul-ticellular glandular hairs on petals, which were foundin Biophytum (Fig. 76) and Averrhoa (Fig. 77) (Oxali-daceae), and Connarus (Connaraceae) (Fig. 78). Sta-mens are congenitally united into a short tube (forConnaraceae, see also Schellenberg, 1938) (Figs 79–81). Epipetalous stamens are considerably reducedand differentiated only as staminodes in some taxa:

Oxalidaceae (Averrhoa, Fig. 80), Connaraceae (Con-narus, occasionally, Fig. 81; for other genera, cf.Schellenberg, 1938; Eimunjeze, 1976). Uniseriate,multicellular (slightly moniliform) glandular hairswere found on stamen filaments in both families(Figs 82,83). Stigmas have multicellular protuber-ances in Oxalis (Fig. 84), Averrhoa (Fig. 85), andConnarus (Fig. 86). Ovules are hemianatropous oralmost orthotropous: Oxalidaceae (Biophytum), Con-naraceae (Cnestis; Connarus) (Schellenberg, 1938;Mauritzon, 1939). Cauliflorous species occur in bothfamilies (e.g. Leenhouts, 1958, for Connaraceae;Veldkamp, 1971, for Oxalidaceae). Furthermore,Behnke (1982) found a unique type of sieve-elementplastids (Pcs’ type) in both Oxalidaceae and Con-naraceae. For other shared non-floral characters, seeNandi et al. (1998). Some authors noticed similaritiesbetween the two families but regarded them as con-vergences (cf. discussion in Jongkind, 1989).

Also Brunelliaceae share some special floral fea-tures with Connaraceae or with both Connaraceae andOxalidaceae, although they do not appear in the sameclade in rbcL analyses (Savolainen et al., 2000).Brunelliaceae and Connaraceae share special featuresin the gynoecium. The ventral slit of each (of theununited or only basally united) carpel tapers down-wards as an external furrow in the ascidiate zone (butalso in Acsmithia of Cunoniaceae) (Figs 60–62). Eachcarpel has two collateral ovules. The vascular bundlesof both ovules form a ventral median bundle in spite ofthe deep ventral slit that is still present at this level.

Brunelliaceae, Connaraceae, and Oxalidaceaeshare an androgynophore (for Connaraceae, cf. alsoDickison, 1971) (in Connaraceae less prominent, butJongkind, 1989, mentions a distinct androgynophorefor Manotes). In some other Oxalidales a rudimentaryandrogynophore was also found but it is less distinct.Nectaries are located in alternisepalous sectors at thebase of the stamens.

Cephalotaceae and CunoniaceaeIn contrast to Oxalidaceae and Connaraceae, Cephal-otaceae and Cunoniaceae, which have also appearedas sisters (Savolainen et al., 2000), did not reveal spe-cial shared characters in floral morphology (apartfrom more general and already known characters). Asister relationship between the two families is notobvious. The monotypic carnivorous Cephalotaceaehave strange autapomorphies, and Cunoniaceae arequite diverse in floral structure.

Elaeocarpaceae and TremandraceaeTremandraceae were once placed close to Pittospora-ceae (see above), with which they share similar flowerforms (solanoid flowers) resulting from an adaptationto buzz-pollination. Thus earlier classifications were



misled by this shared syndrome of floral features.Ironically, the new placement close to, and even nestedwithin Elaeocarpaceae, suggested by molecular stud-ies (Savolainen et al., 2000; Soltis et al., 2000), is againassociated with a group exhibiting the same syndromeof solanoid flowers. However, our present morphologi-cal study revealed that there are many additionalshared characters between Tremandraceae and Elae-ocarpaceae than just those of the buzz–pollinationsyndrome. Thus, our results greatly support thisnewly established relationship.

The shared characters that are probably involved inthe buzz–pollination syndrome are as follows. Flowersare often pendant (Figs 45–47), and it is perhaps aconsequence of the pendant habit that the perianthbase is bulged backwards in some taxa (Crinodendron,Platytheca). Stamen filaments are short, shorter thananthers immediately before anthesis (in all taxa herestudied of these two families, except for Vallea inwhich they are of equal length) (Figs 48–51). Anthersare basifixed (in all taxa studied, both families).Anther dehiscence is poricidal, either by two short api-cal slits (Aristotelia; Sloanea; Vallea, Fig. 52), or by asingle apical pore (Crinodendron, Fig. 53; Elaeocarpus;Platytheca, Fig. 54; Tetratheca, Fig. 55). The endoth-ecium is continuous over the dorsal and ventral part ofthe anther in all taxa studied of the two families(Fig. 56J–N); in addition, in Tremandraceae it forms acontinuous cylinder around the anther, and cells donot have differential cell wall thickenings as in normalendothecium; rather they are thickened on all sides oreven more so on the outer than the inner side. Stigmasare punctiform in Elaeocarpus, Sloanea (but also in thenectariferous Crinodendron) (Fig. 93), and Treman-draceae (Fig. 94). Punctiform rather than extendedstigmas seem to be advantageous for the operation ofelectrostatic forces in buzz-pollination (Vaknin et al.,2000). Nectaries are absent in Sloanea, Platytheca andTetratheca (present in Tremandra; Rani, 1995). It issurprising that Crinodendron with pendant flowersand punctiform stigma is nectariferous and is animal-pollinated; C. hookerianum even produces large quan-tities of nectar and is pollinated by hummingbirds(Bricker, 1992) (the prominent midrib together withthe induplicate flanks in the petals may serve as anefficient nectar holder). Could it be that these flowersare secondarily nectariferous, derived from solanoidpollen flowers with some characteristics of those stillretained?

Significantly, between the two families there are anumber of shared features that have no obviouscorrelation with buzz-pollination. Petals are largerthan sepals in advanced buds (Crinodendron, Fig. 87;Tetratheca, Fig. 89) and form the protective layer forthe inner organs in bud; adjacent petals are valvate,the flanks are involute and enclose part of the stamens

or all stamens in Crinodendron (Fig. 88) and Elaeocar-pus (Elaeocarpaceae), and in Platytheca and Tetratheca(Tremandraceae) (Fig. 90). In addition, in all thesetaxa with wrapped stamens, the petal base is broad.Petals have three vascular traces in Crinodendron andVallea (Elaeocarpaceae) (more specifically, in Valleathere is only one trace, but the three main bundlesgo down into the floral base until they merge intoone trace), and Platytheca and Tetratheca (Treman-draceae). Lignified hairs on anthers were found in allElaeocarpaceae studied and in Platytheca (Treman-draceae) (Figs 91,92) (among the other taxa studiedonly Connarus (Connaraceae) has this feature). Thereis a tendency for distribution of tanniferous tissue inthe dorsal region of those stamens that form the outerseries in the androecium (Sloanea and Platytheca);thus, the androecium seen as a whole is tanniferous atits periphery, giving the impression of having an outerprotective layer. Lignified hairs were found inside theovary locule (Crinodendron, Fig. 95; Vallea; Tetratheca,Fig. 96; but also in Oxalis; for Oxalis, see also Sauer,1933). Hairs are present on the ovules (Elaeocarpus,Platytheca) (Figs 97,98,100,101). Hairs on seeds arealso present in some Cunoniaceae (Engler, 1930c;Dickison, 1984) but were not reported from ovules,and thus may develop only after anthesis (for Wein-mannia, personal observations; Govil & Saxena,1976). Two lateral ovules per carpel are present,partly one above the other (Aristotelia, Vallea, Tetrath-eca). The ovules have a chalazal appendage (Aristote-lia, Fig. 99; Vallea; Tetratheca, Fig. 102) (but alsoOxalis, Fig. 72); at least in Tremandraceae it developsinto an elaiosome in the seed (Berg, 1975). The innerintegument is much thicker than the outer andreaches a thickness of 10 or more cell layers in repre-sentatives of both families (e.g. Platytheca, Fig. 73).

COMPARISON OF OXALIDALES WITH OTHER GROUPS

Geraniales and MalpighialesFlowers with isomerous whorls, including obdiploste-mony, stamen filaments basally congenitally unitedinto a tube (Kumar, 1976), and nectaries at the outerbase of stamen filaments, are common in families ofOxalidales, Geraniales and a few Malpighiales. Apartfrom Oxalidales, basal union of stamen filamentsispresent, e.g. in some Geraniaceae (Sauer, 1933),Ixonanthaceae (Narayana & Rao, 1978a), Linaceae(Narayana & Rao, 1978b), Hugoniaceae (Narayana &Rao, 1977b), and Humiriaceae (Cuatrecasas, 1961;Narayana & Rao, 1977a). As in Oxalidaceae, in Gera-niaceae, Ixonanthaceae, Linaceae, Hugoniaceae, andHumiriaceae, corolla aestivation is predominantlycontort. As in Oxalidales, in Geraniaceae, Humiri-aceae, Linaceae, and Erythroxylaceae, epipetalousstamens tend to be shorter than episepalous, and



sometimes staminodial (Narayana & Rao, 1978c). Theoriginally introrse anthers flip backwards at anthesisin Oxalidaceae, Geraniaceae, and Linaceae and someother, unrelated families (Hallier, 1923); this was alsofound in Cunoniaceae (Barnes & Rozefelds, 2000) andConnaraceae (this study). Heterostyly is present inErythroxylaceae (e.g. Ganders, 1979). Heterostyly,including tristyly, as in Oxalidaceae and Connaraceae,was reported from Hugoniaceae (Thompson et al.,1996). Lignified hairs inside the ovary locule, as insome Oxalidales, are also present in some Gerani-aceae (Sauer, 1933). Ovules have obturators inBrunelliaceae and Tremandraceae (for Treman-draceae, see also Boesewinkel, 1999); this is also truefor Euphorbiaceae s.l. and some other Malpighiales(Sutter & Endress, 1995). As in Oxalidaceae, inMalpighiales ovules are often (incompletely) tenui-nucellar, such as in Linaceae, Dichapetalaceae,Chrysobalanaceae, Ochnaceae, Trigoniaceae, Clusi-aceae and Podostemaceae (review in Endress, 2002),and there is an endothelium (Boesewinkel, 1980); boththese features are otherwise rare in rosids (cf. alsoPhilipson, 1974, 1977). Hypseocharis was transferredfrom Oxalidaceae to Geraniales (cf. Hallier, 1923;Boesewinkel, 1988; Rama Devi, 1991): double positionof stamens is also present in Monsonia (Geraniaceae)but not in Oxalidaceae; and nectaries are alternipeta-lous as in Geraniaceae; this transfer also reflects thesimilarity in floral structure between the two families.

CucurbitalesThe striking similarities in floral structure betweenCunoniaceae and Anisophylleaceae (Cucurbitales)were shown and discussed by Matthews et al. (2001).An additional shared feature is that specialized idio-blasts with unequally thickened mucilaginous cellwalls are not only present in sepals but were alsofound in the carpel wall in both families, Cunoniaceae(Geissois), Anisophylleaceae (Anisophyllea), but not inother Oxalidales. Similar to Oxalidales, Cucurbitalesin the current circumscription (APG, 1998; Savolainenet al., 2000; Soltis et al., 2000) are an assemblage offamilies that were formerly distant from each other.Therefore, they are also in need of comparative mor-phological studies.

CONCLUSIONS

The close relationships between Oxalidaceae and Con-naraceae, and between Elaeocarpaceae and Treman-draceae are strongly supported by the present studyand by some earlier morphological results adducedfrom the literature. However, there is no additionalsupport for a close relationship between Cephalota-ceae and Cunoniaceae (which were also in proximityin earlier classifications).

Future studies should encompass an in-depth treat-ment of floral structure over a broad range of the cur-rent clades of early branching core eudicots, andespecially other orders of rosids, such as Geraniales,Malpighiales and Myrtales, as the rosids are the leastresolved large clade in core eudicots. In addition, theproblematical Saxifragales should also be studied.Only then can a comprehensive cladistic analysis beenvisaged and, in turn, an evaluation of the evolutionof floral features based on more refined molecular phy-logenetic studies of basal core eudicots.

ACKNOWLEDGEMENTS

For valuable pickled plant material we thank A.Bohte, A. George, J. Gomez-Laurito, A. M. Juncosa, T.McFarlane, J. Schönenberger, and M.von Balthazar.The second author thanks V. Bittrich, B. Gray, and B.P. M. Hyland for support in the field. Information on avariety of topics by V. Bittrich, S. S. Renner and D. E.Soltis is gratefully acknowledged. We thank U. Jauchfor support with the SEM, and R. Siegrist for some ofthe microtome sections. Collection trips of the secondauthor to Papua New Guinea, Queensland and NewCaledonia were supported by the Georges-und-Antoine-Claraz-Schenkung. Support by the DeepTime Project (US National Science Foundation) is alsoacknowledged. This study is part of a project of P.K.E.financially supported by the Swiss National ScienceFoundation (grant nr.3100–059149.99/1).

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