Ecological distribution of cellular slime molds in forest ...€¦ · Bot Relv 105: 199-219 0253-1453/95/020199-21 $1.50+0.20/0 @ 1995 Birkhiiuser Verlag, Basel Ecological distribution

Bot Relv 105: 199-219 0253-1453/95/020199-21 $1.50+0.20/0@ 1995 Birkhiiuser Verlag, Basel

Ecological distribution of cellular slime moldsin forest soils of GermanyJames C. Cavender 1, Jeannine Cavender-Bares 2 and Hans R. Hohl31 Department of Environmental and Plant Biology, Ohio University, Athens, Ohio 457011-2979

USA2 Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massa-

chusetts 02138 USA3 I!lstitute of Plant Biology, University of Zurich, Zollikerstr. 107, CH-8008 Zurich, Switzerland

Manuscript accepted September 18, 1995

Abstract

Cavender J. C., Cavender-Bares J., and Hohl H. R. 1995. Ecological distribution ofcellular slime molds in forest soils of Germany. Bot. Helv. 105: 199-219.

Surface soils were collected from deciduous, coniferous and mixed coniferous-decid-uous forest of Germany during the latter half of July 1993 and were plated out for cellularslime molds at Ohio University during the first half of August, 1993. Twenty-four siteswere sampled from different geographical regions in southern, central and westernGermany. Germany has a fairly diverse cellular slime mold flora/fauna similar to that ofthe cool temperate zone of Japan and to the North American bi-state region of Ohio andWest Virginia. Eighteen morphological species were isolated which match those de-scribed in the literature. Three entities were isolated only once, hence are considered tobe rare: Acytostelium leptosomum, Dictyostelium capitatum, and a new species, Dictyos-telium germanicum. Four species originally described from Japan were isolated for thefirst time from Europe: Dictyostelium microsporum, D. capitatum, D. implicatum andPolysphondylium candidum. The most commonly isolated were Dictyostelium mucoroides,S-type and Polysphondylium violaceum. Cellular slime mold populations of deciduousand coni(erous forests have distinct differences. Numbers of clones per gram and speciesrichness were higher in soils of deciduous forests than in coniferous forests.

Key words: Cellular slime mold, dictyostelid, ecological distribution, forest soil.

Introduction

Cellular slime molds were introduced to the world by Oskar Brefeld, a Germanmycologist, with his report of the discovery of Dictyostelium mucoroides in 1869. He alsodescribed Polysphondylium violaceum (1884), although he did not find these cellular slimemolds in.(orest soils. Oehler (1922), working in Wiirzburg, reported that D. mucoroidescould be isolated from forest soil. We have found these two species to be the mostcommon in Central Europe. Hagiwara (1984) has assembled evidence to show that

199

200 James C. Cavender et al.

Brefeld's description of D. mucoroides matches most closely another cosmopolitan spe-cies which Raper (1984) designated as D. sphaerocephalum (Oud.) Sacco et March.Hagiwara created the name D. brefeldianum for the taxon we are naming D. mucoroides,S-type. Because there is no holotype designated and preserved from Brefeld's description,we are, for the time being, using Raper's taxonomy.

Cavender (1969) was the first to make an ecologically-based distributional study ofEurope. However, only two sites were sampled in Central Europe, one in West Germanyand one in Switzerland. Traub (1972) later did a comprehensive survey of cellular slimemolds in Switzerland which was augmented by further collections of Cavender andpublished in 1981 (Traub, Hohl and Cavender 1981 a, 1981 b). Three new species weredescribed: Dictyostelium fasciculatum, D. polycarpum, and Polysphondylium filamento-sum. Traub also designated two types of D. mucoroides as Sand L types. This differen-tiation of D. mucoroides has been continued in this study. They may represent distinctspecies. Leitner (1987) made some interesting observations of three cellular slime moldswith respect to forest soil pH. He found Dictyostelium mucoroides and D. fasciculatummore prevalent in deciduous forest with neutral or slightly alkaline soils while D. minu-turn was more common in deciduous forest soils which were acidic (ca. pH 5.0).

In this study, Dictyostelium implicatum Hagiwara, D. microsporum Hagiwara,D. capitatum Hagiwara, D. germanicum nsp., D. septentrionalis Cavender, and Poly-sphondylium candidum Hagiwara are reported for the first time from Europe. Dictyoste-lium germanicum was isolated from a mature beech forest within a Tertiary volcanic conein the Eifel region of the Rhineland Palatinate. It is unique in having small solitarysorocarps bearing oblong spores with numerous unconsolidated polar granules.

Study Area

Germany, with an area of357,000 square kIn, has a great diversity of topography andsoils due to a rather complex orogeny. Among the microenvironments present are thoseinfluenced by glacial till, including sand and bog environments, limestone, sandstone andbasaltic bedrock, as well as considerable loess deposits in certain areas. Most of thecountry is broken into mountains and valleys by a network of rivers of considerablewater volume indicative of an abundant rainfall distributed throughout the year (Ellen-berg 1988). Air temperature in summer seldom exceeds 30°C and in winter -20°C."Such a climate encourages the universal growth of trees" (Ellenberg 1988). Despiteconsiderable agricultural activity, Germany still has over one third of its land in forest.The climate favors beech (Fagus sylvatica) and oak (Quercus robur) but there are alsosome deciduous woodlands with an assortment of dominants such as maple (Acer) andlinden (Tilia). Conifers, spruce (Picea abies) and Scots pine (Pinus sylvestris) are naturallydominant in the northeast and at higher elevations although much of the deciduousforest of central and western Germany has been replaced by conifer plantations.

Methods

Fifty gram soil samples were collected in Whirl Pac plastic bags during late July and earlyAugust 19~ and processed for Dictyostelidae in a way similar to that reported by Cavender andRaper (1965). However, all cultures were shaken by hand rather than by machine. All of the soilswere processed during late August 1993 at Ohio University upon return from Germany.

Botanica Helvetica 105/2, 1995 201

The method of analyzing dictyostelid populations in soil is based on the appearance of clonesof cellular slime molds on a dilute hay-infusion agar surface which has been inoculated with anappropriate soil dilution and a pre-grown bacterial food supply. Colonies of the developing organ-isms are identified and counted in the isolation plates. Unidentifiable colonies are removed totwo-membered cultures with Escherichia coli Blr for further study. The acrasian populations in eachforest are expressed in terms of frequency, relative density, and density (Tables 2-4). Density is thetotal number of clones per gram of soil while frequency is the number of times a species occurs ata particular site expressed as a percentage, and relative density is the relative number of colonies ofeach species at a site expressed as a percentage. Isolates of each species were cultivated on non-nu-trient agar with 24 hour pre-grown E. coli and preserved by lyophilization in the Kenneth B. Rapercellular slime mold collection housed at Ohio University. Soil pH was measured in the lab using aRadiometer ION83 ION METER. Photomicrographs were taken using an Olympus phase contrastmicroscope.

Forests in foothills, mountainous areas and lowlands were sampled in central, western, andsouthern Germany (Fig. 1). The lowlands of northern and eastern Germany, however, were exclud-ed due to time constrai~ts except for one site (LH). Characteristics of each site are listed in Table 1.These include location, date of collection, geographical region, forest type, dominant trees, geolog-ical features, elevation, humus type and soil pH.

Results

The results of the distributional study are presented in Tables 2-4. Dictyostelidsrecovered from soils of coniferous or mixed coniferous deciduous forest are presented inTable 2, dictyostelids recovered from neutral or alkaline soils in deciduous forests arepresented in Table 3, and dictyostelids recovered from acid soils in deciduous forests arepresented in Table 4. Comparisons of the cellular slime mold populations in these threeenvironments within Germany can, therefore, be made more easily.

Eighteen of the nineteen species isolated are illustrated with photomicrographs inFigs. 2-55. Spores, aggregation pattern and sorocarps are reproduced. Descriptions ofthese species except for Traub's D. mucoroides L-type may be found in either Raper's(1984) or Hagiwara's (1989) monographs, therefore our comments are limited to salientfeatures. A description and Latin diagnosis of D. germanicum is presented here.

Dictyostelium germanicum Cavender, Cavender-Bares, et Hohl sp. novo (Figs. 50,51, 52) Sorocarpia plerumque solitaria, erecta, magnitudine regularissima, normaliter0.5-1.5 mm longa, ecolorata; sorophoria cellulis uniserialiter dispositis, diametro basalicirca 23-26 J.Ufi ad 4-6 J.Ufi angustata ad apicem; sori globosi 60-120 J.Ufi; aggregationestumuliformes 160-260 !lm, interdum margine brevibus radiis striatae, sporae ellipticaeobtusae, plerumque 3-4 x 6-8 !lm granulis polaribus non consolidatis, Stirps typica:ME-1. Sorocarps usually solitary, erect, very uniform in size, usually 0.5-1.5 mm long,unpigmented, sorophores with a single tier of cells taper from about 23 -26 !lm at thebase to 4-6 !lm at the tip; sori spherical mostly 60-120 !lm in diameter; aggregationsmound-like 160-260 !lm, sometimes with short streams, spores elliptical with blunt ends,mostly 3-4 x 6-8!lm with numerous unconsolidated polar granules. Type strain ME-1deposited in Kenneth B. Raper dictyostelid collection at Ohio University.

Habitat: leaf mold of a mature beech forest located within a volcanic cone of the Eifelregion in the Rhineland Palatinate.-1. D. mucoroides, S-type, RO-1b, Figs. 2-4. Unpigmented, single large sorocarps withbasal discs of supporting cells, radiate aggregates, spores without polar granules.

202 James C. Cavender et at.

Table 1. Collection sites.

Geologic features: Mountain, basalt cliffsElevation: 200-500 mHumus type: mullSoil pH: 4.7RS Site: RothaargebirgejSiegenDate: 7.26.93Region: RothaargebirgeForest type: Mixed coniferous-deciduousDominant trees: Beech, Oak, SpruceGeologic features: mountainousElevation: 600 mHumus type: morSoil pH: 4.8

Niedersachsen (Lower Saxony)LH Site: Liineburger Heide

Date: 7.29.93Region: Liineburger Heide(Luneberg Heath)Forest type: Mixed coniferous-deciduousDominant trees: Beech (Fagus),Oak (Quercus), Birch (Betula),Pine (Pinus), Spruce (Picea)Geologic features: glacial moraineElevation: 50-100 mHumus type: morSoil pH: 3.6

TH Site: TorfllausjHarzDate: 7.30.94Region: HarzForest type: ConiferousDominant trees: SpruceGeologic features: mountainousElevation: 800 mHumus type: morSoil pH: 3.8

Rheinland-Pfalz (Rhineland Palatinate)KM Site: Kobern/Mosel

Date: 7.23.93Region: Eifel, Mosel ValleyForest type: DeciduousDominant trees: Hornbeam (Ostrya)Geologic features: elevated terrain alongMosel riverElevation: 150-250 mHumus type: mullSoil pH: 4.2

ME Site: Miiuseberg/EifelDate: 7.21.93Region: EifelForest type: DeciduousDominant trees: Beech, Hawthorn(Crataegus)Geologic features: north facing slope oflake basinElevation: 450-550 mHumus type: mullSoil pH: 5.7

Hessen (Hesse)RG Site: Rheingau

Date: 7.20.93Region: Rheingaugebirge, TaunusForest type: DeciduousDominant trees: Chestnut (Castanea),Oak, Cherry (Prunus), Hawthorn,BasswoodGeologic features: elevated terrain alongRhine riverElevation: 450-500 mHumus type: mullSoil pH: 4.5

Nordrhein- Westfalen(North Rhine Westphalia)KV Site: Kottenforstville in Bruhl

Date: 7.23.93Region: Rhine Valley,northern Rheinisches SchilefergebirgeForest type: DeciduousDominant trees: Basswood (Tilia),Maple (Acer), BirchGeologic features: glacial lake basinElevation: 150 mHumus type: mullSoil pH: 7.0

EW Site: Elmpter Wald/Dutch BorderDate: 7.23.93Region: Niederlandisches Tiefland(Dutch lowland)Forest type: Mixed coniferous-deciduousDominant trees: Pine, Oak, BirchGeologic features: glacial moraineElevation: < 100 mHumus type: morSoil pH: 4.8

DR Site: Drachenfels/RheinDate: 7.25.93Region.:. SiebengebirgeForest type: DeciduousDominant trees: Beech

Botanica

Helvetica 105/2, 1995 203

Table Collection sites (continued).

Dominant trees: BeechGeologic features: lake shoreElevation: 400 mHumus type: moderSoil pH: 4.4KS

Site: KaiserstuhlDate: 8.9.93Region: Schwarzwald (Black Forest)Forest type: ConiferousDominant trees: Hazel Nut (Corylus),Maple, Beech, Ash, Locust (Robinia),Poplar (Populus)Geologic features: loess depositsElevation: <450 mHumus type: mullSoil pH: 7.6

TN Site: Taunus summitDate: 7.20.93Region: TaunusForest type: DeciduousDominant trees: Alder (Alnus) Birch,Beech, Larch (Larix), OakGeologic features: mountainous gorgeElevation: 500 mHumus type: mullSoil pH: 4.5

SO Site: StarkenbergjOdenwaldDate: 8.9.93Region: OdenwaldForest type: DeciduousDominant trees: Walnut (Juglans), Maple,Beech, Sycamore (Platanus), Oak,Chestnut, Basswood, Ash (Fraxinus)Geologic features: limestone parentmaterialElevation: 500 mHumus type: mullSoil pH: 7.0

Baden- WurttembergRO Site: Rothenburg ob der Tauber

Date: 8.4.93Region: Schwiibisch-FriinkischesStufenlandForest type: DeciduousDominant trees: Walnut, Maple, Birch,BasswoodGeologic features: limestone parentmaterial, steep slopeElevation: 450-500 mHumus type: mullSoil pH: 7.7

EB Site: EriskirchjBodenseejReid NaturschutzgebietDate: 8.7.93Region: Lake Constance,below Schwiibische AlbForest type: DeciduousDominant trees: Oak, BirchGeologic features: lake shoreElevation: 400 mHumus type: mullSoil pH: 6.9

EK Site: EriskirchjBodenseeDate: 8,7.93Region: Lake Constance,below Schwiibische Alb

Bayern (Bavaria)WO Site: Wonsee/Friinkische Schweiz

Date: 8.2.93Region: Friinkische SchweizForest type: Mixed coniferous-deciduousDominant trees: Oak, Alder, Beech,Ironwood (Carpinus), Basswood,Hornbeam, Spruce, BirchGeologic features: limestone outcropsElevation: 400-450 mHumus type: mullSoil pH: 7.0

HS Site: Haag/SteigerwaldDate: 8.3.93Region: SteigerwaldForest type: Mixed coniferous-deciduousDominant trees: Beech, Spruce, Oak,Pine, BirchGeologic features: sandstone ravineElevation: 450 mHumus type: moderSoil pH: 4.6

DF Site: Danube, west of IngolstadtDate: 8.5.93Region: Danube flood plane,Friinkische AlbForest type: DeciduousDominant trees: AshGeologic features: Danube riverflood plainElevation: 380 mHumus type: mullSoil pH: 7.3


Table 1. Collection sites (continued).

Ff Site: FriedrichrodafThiiringer WaldDate: 7.31.93Region: Thiiringer WaldForest type: Mixed coniferous-deciduousDominant trees: Spruce, Birch, Beech,Maple, Hazel Nut, AlderGeologic features: bordering an uplandswampElevation: 600-800 mHumus type: moderSoil pH: 3.5

SV Site: Spitzing-SeejVoralpenDate: 8.6.93Region: Bayerische Alpen (Bavarian Alps)Forest type: ConiferousDominant trees: Spruce, Fir (Abies)Geologic features: steep mountain slope,limestone parent materialElevation: 1200-1500 mHumus type: mullSoil pH: 7.3Comments: forest die-back evident

Thiiringen (Thuringia)DH Site: Barbarossahohle

Date: 7.30.93Region: Thiiringer Becken, HainleiteForest type: DeciduousDominant trees: Maple, OakGeologic features: limestone,Karst topographyElevation: 200-250 mHumus type: mullSoil pH: 7.3

SH Site: SondershausenDate: 7.30.93Region: Thiiringer Becken, HainleiteForest type: DeciduousDominant trees: OakGeologic features:Elevation: 200-250 mHumus type: mullSoil pH: 4.7

Freistaat Sachsen (Free State of Saxony)HE Site: HomersdorfjErzgebirge

Date: 8.2.93Region: Sachsisches Bergland just abovethe ErzgebirgeForest type: ConiferousDominant trees: SpruceGeologic features: mountainousElevation: 550 mHumus type: mOTSoil pH: 3.5

FB Site: FichtelbergjCzech borderDate: 8.2.93Region: ErzgebirgeForest type: ConiferousDominant trees: SpruceGeologic features: mountainousElevation: 1200 mHumus type: mOTSoil pH: 3.7Comments: serious forest die-back

2. D. mucoroides, L-type, KS-2, Figs. 5-7. Unpigmented, single, large phototrophicsorocarps; sorophores without basal discs, radiate aggregations develop distinctivelumpy centers, sorogens elongated, slightly larger spores than S-type, spores withoutpolar granules.3. D. implicatum, HS-4, Figs. 8-10. Radiate aggregation, robust solitary sorocarps withbasal discs become tangled when grown in diffuse light; spores tend to germinate to formsecondary sorocarps, spores without polar granules and larger than those of D. mu-coroides S-type.

4. D. aux.eo-stipes var. aureo-stipes, RO-4, Figs. 11-13. Irregularly branched flexuoussorocarps with yellow sorophores when grown in the dark; aggregates break up intosmaller centers; spores with conspicuous consolidated polar granules.

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Fig. 1. Map of Germany showing the locations of the twenty-four collection sites. LH -LuneburgerHeide, TH -TorfhausjHarz, KV -Kottenforstville in Bruhl, EW -Elmpter WaldjNetherlandsborder, DR -DrachenfelsjRhein, RS -RothaargebirgejSiegen, KM -KobernjMosel, ME -MiiusebergjEifel, RG -Rheingau, TN -Taunus summit, SO -StarkenbergjOdenwald, RO -Rothenburg ob del Tauber, EB -EriskirchjBodenseejReid Naturschutzgebiet, EK -EriskirchjBodensee, KS -Kaiserstuhl, WO -WonseesjFriinkische Schweiz, HS -HaagjSteigerwald, DF -Danube f1~dplain, Ingolstadt, SV -Spitzing-SeejVoralpen, BH -Barbarossahohle, SH -Sonder-hausen, FT -FriedrichrodajThuringer Wald, HE -HomersdorfjErzgebirge, FB -Fichtelbergj

Czech border.



Figs. 11-19. Photomicrographs of Dictyostelium aurea-stipes var. aurea-stipes, D. aurea-stipes var.helvetium and Polysphondylium violaceum. 11-13. D. aurea-stipes var. aurea-stipes. 11. Spores,x 750. 12...Aggregation, x 40. 13. Sorocarps, x 40.14-16. D. aurea-stipes var. helvetium. 14. Spores,x 750. 15. Aggregation, x 40. 16. Sorocarps, x 40. 17-19. P. violaceum. 17. Spores, x 750.

18. Aggregation, x 40. 19. Sorocarps, x 40.


Figs. 20-28. Photomicrographs of Polysphondylium pallidum, P. filamentosum and P. candidum.20-22. P...pallidum. 20. Spores, x 750. 21. Aggregation, x 40. 22. Sorocarps, x 40. 23-25.P.filamentosum. 23. Spores, x 750. 24. Aggregation, x 40. 25. Sorocarps, x 40. 26-28. P. can-

didum. 26. Spores, x 750. 27. Aggregation, x 40. 28. Sorocarps, x 40.


Figs. 29-37. Photomicrographs of Dictyostelium septentrionalis, D. sphaerocephalum, and D.fasci-culatum. 29-.J1. D. septentrionalis. 29. Spores, x 750.30. Aggregation, x 40.31. Sorocarps, x 40.32-34. D. sphaerocephalum. 32. Spores, x 750.33. Aggregation, x 40.34 Sorocarps, x 40.35-37.

D. fasciculatum. 35. Spores, x 750. 36. Aggregation, x 40. 37. Sorocarps, x 40.


Figs. 38-46. Photomicrographs of D. polycarpum, D. microsporum and Acytostelium leptosomum.38-40. D. }I(Ilycarpum. 38. Spores, x 750. 39. Aggregation, x 40. 40. Sorocarps, x 40. 41-43.D. microsporum. 41. Spores, x 750. 42. Aggregation, x 40. 43. Sorocarps, x 40. 44-46. Acytosteli-

um leptosomum. 44. Spores, x 750. 45. Aggregation, x 40. 46. Sorocarps, x 40.

214 James C. Cavender et at.

Figs. 47-55. Photomicrographs of Dictyostelium minutum, D. germanicum, and D. capitatum.47-49. 1). minutum. 47. Spores, x 750. 48. Aggregation, x 40. 49. Sorocarps, x 40. 50-52.D. germanicum. 50. Spores, x 750. 51. Aggregation, x 40.52. Sorocarps, x 40.53-55. D. capitatum.

53. Spores, x 750. 54. Aggregation, x 40. 55. Sorocarps, x 40.


5. D. aureo-stipes var. helvetium, FT-l, Figs. 14-16. Irregularly branched sorocarps,robust and erect sorocarps with yellow sorophores when grown in the dark; aggregatesbreak up into smaller units, spores with conspicuous consolidated polar granules.

6. P. violaceum, FT-5, Figs. 17-19. Purple to violaceous pigmentation of sorocarps,whorled branches; aggregates break up, spores with consolidated polar granules.

7. P. pal/idum, LH-4, Figs. 20-22. Unpigmented sorocarps, numerous whorls ofbranches, radiate aggregation, spores with unconsolidated polar granules.

8. P.filamentosum, RS-5, Figs. 23-25. Distinguished by the elongated terminus of themain axis as well as the axes of the whorled branches of the sorocarps, radiate aggrega-tion, unconsolidated polar granules.

9. P. candidum, ME-2, Figs. 26-28. Unpigmented sorocarps, terminal segment may beelongated, radiate aggregation, more robust than P. pal/idum with fewer whorls, largespores with unconsolidated polar granules.

10. D. septentrionalis. FB-l, Figs. 29-31. Very robust thick sorocarps often with ex-panded bases, radiate aggregations, will not grow above 20 °C, large spores without polargranules.11. D. sphaerocephalum, KS-5, Figs. 32-34. Small but stout sorocarps, characterized bythick sorophore tips with slime collars and well developed supporters of prostatesorophores, spores without polar granules.

12. D.jasciculatum, RO-la, Figs. 35-37. Several sorocarps per aggregate, aggregatesbreak up, conspicuous consolidated polar granules.

13. D. polycarpum, KS-4, Figs. 38-40. Small coremiform sorocarps, mound-like aggre-gates or short streams, relatively long spores with conspicuous unconsolidated polargranules.14. D. microsporum, HE-4, Figs. 41-43. Several delicate sinuous sorocarps develop froman aggregate, aggregates mound-like developing a lobed stream network when older,spores of two sizes with conspicuous consolidated polar granules.

15. Acytostelium leptosomum, DR-4, Figs. 44-46. Minute size; mound-like aggregates,sometimes with streams; acellular, very delicate sorocarps; spherical spores.

16. Dictyostelium minutum, HS-2, Figs. 47-49. Small size; mound-like aggregation withreverse streaming when older, solitary or more commonly several sorocarps per aggre-gate, spores with or without inconspicuous polar granules.

17. D. germanicum, ME-l, Figs. 50-52. Small size; mound-like aggregates; single soro-carp per aggregate; oblong spores with numerous unconsolidated polar granules.

18. D. capitatum, TH-2, Figs. 53-55. Delicate; mound-like aggregates or short, coarsestreams; several sorocarps per aggregate; sorophores with capitate tips; spores withinconspicuous polar granules.19. D. giganteum, FT -2, not illustrated. Very similar to D. mucoroides S-type with muchlonger erector creeping sorophores.-


Key to the dictyostelids of Germany

Sorophores acellular (Acytostelium)spores spherical, sorocarps very delicate Acytostelium leptosomum

(Figs. 44-46)1. Sorophores cellular, spores elliptical. 22. Sorocarps unbranched or branched but never with whorled branches (Dictyostelium )2. Sorocarps typically with whorls of branches (Polysphondylium) .3. Sorocarps pigmented, sorophores and son violet to purple. ..

3Polysphondylium violaceum

(Figs. 17-19)4

Polysphondylium pa//idum(Figs. 20-22)

5

3. Sorocarps unpigmented4. Whorls numerous. ..

4.Whorlsfew 5. Lateral branch tips elongated, tips of main axis also elongated

Polysphondylium filamentosum(Figs. 23-25)

5. Lateral branches not elongated, main axis tips may be elongatedPo/ysphondy/ium candidum

(Figs. 26-28)6. Sorocarps unpigmented and without whorled branches. 86. Sorocarps pigmented, sorophores yellow in reduced light or darkness. 77. Sorophores erect, branched, spores with conspicuous polar granules,

conifer or mixed coniferous deciduous forests. .Dictyoste/ium aureo-stipes var. he/vetium(Figs. 14-16)

7. Sorophores prone or flexuous, branched; spores with conspicuous polar granules;deciduous forest. Dictyoste/ium aureo-stipes var. aureo-stipes

(Figs. 11-13)8. Sorocarps small, mostly < 2 mm high, sorophores composed of a single tier of cells.. 158. Sorocarps medium, large or very large >2 mm to 1.5 cm, sorophores composed

of more than one cell incross section 99. Aggregation large, radial, do not break up 109. Aggregations large, initially radial but break up into numerous smaller aggregations,

sorocarps clustered, spores with conspicuous polar granules, abundant in deciduous forestswith neutral or alkaline humus. Dictyoste/ium fascicu/atum

(Figs. 35-37)

10.

Sorocarps very large, reaching 5-15 mm in height. 1110. Sorocarps large but mostly <5 mm unless exposed to one-sided illumination. 1211. Sorocarps erect, robust 1.0-1.5 cm high, very large sori (up to 500 1Un), arising from

expanded, conical bases; will not fruit above 20 °c Dictyostelium septentrionalis

(Figs. 29-31)11. Sorocarps erect, 5-10 mm high, or commonly greatly elongated by migration, up to several cm

in length. Dictyosteliumgiganteum

(not illustrated)12. Sorocarps mostly 2-5 mm when erect, sorophores partially prostrate showing little taper,

sori relatively large, 175-350 ~m in diameter with cupule-like residuesat bases of sori Dictyostelium sphaerocephalum

(Figs. 32-34)12. Sorocarps mostly 2-5 mm when erect unlike the above. 1313. Sorocarps becoming entangled in diffuse light, spores of collapsed sori germinate

to form secondary sorocarps with basal discs. Dictyostelium implicatum

(Figs. 8-10)13. Sorocarps not becoming entangled in diffuse light. 14


14. Sorocarps with slightly expanded conical bases. Dictyoste/ium mucoroides, S-type

(Figs. 2-4)14.

Sorocarps without expanded bases, aggregations assume a "lumpy" appearance in late stages,

sorogens elongated, sorophores migrating extensively. .Dictyoste/ium mucoroides, L-type

(Figs. 5- 7)

15. Sorocarps clustered, aggregations usually mound-like. 1815. Sorocarps solitary or weakly clustered, aggregations usually mound-like. 1616. Spores oblong 3-4 x 6-81!m with numerous conspicuous unconsolidated

polar granules. Dictyostelium germanicum(Figs. 50-52)

16. Spores smaller mostly 2-3 x 4-61!m with inconspicuous polar granules. 1717. Sorophore tips capitate, coniferous or mixed coniferous deciduous forest

Dictyosteliumcapitatum(Figs. 53-55)

7. Sorophore tips not capitate, abundant in deciduous forest with acid humusDictyosteliumminutum

(Figs. 47 -49)18. Sorocarps in coremiform clusters, spores long, with numerous conspicuous

unconsolidated polar granules. Dictyostelium polycarpum(Figs. 38-40)

18. Sorocarps in irregular clusters, spores small and of two sizes both with conspicuousconsolidated polar granules. Dictyostelium microsporum

(Figs. 41-43)

Discussion

With 19 species, the region studied in Germany has very similar species richness toboth the bistate region of Ohio and West Virginia and the cool temperate zone of Japan.This could be the result of close similarity in the degree of topographical, geographicaland forest variation.

Some species, are plentiful and common on all three continents, such as Dictyosteliummucoroides S type, D. sphaerocephalum, D. minutum, Polysphondylium pallidum andP. violaceum. Others are absent or very infrequent on one continent while they areprevalent on one or both of the others. The species which are absent or relativelyinfrequent in Europe but common in North America and Japan include D. discoideum,D. purpureum, and D. polycephalum. Those absent or less frequent in Eastern NorthAmerica but more common in Europe are P. candidum, P.filamentosum, D. polycarpum,D. septentrionalis, and D. implicatum. The last two species appear to be more commonin the Pacific Northwest than elsewhere in North America (Cavender, unpublished data).D. fasciculatum is an endemic to Europe.

Three new species not found in Switzerland or elsewhere in Europe occur in Ger-many. One of these, D. capitatum, was isolated from a mixed coniferous-deciduous forestin the Harz mountains on the former border between East and West Germany, while thesecond, D. germanicum, occurred in a deciduous forest in the Eifel region of RhinelandPalatinate. The most common of the three, D. microsporum, was found at three separateconiferous sites. This is a fairly common species in mixed coniferous-deciduous forest inJapan. -

Coniferous forests with acid mor humus and deciduous forests with neutral oralkaline mull humus have distinct differences in their dictyostelid populations. Numbers


per gram are higher in deciduous forests, even those with acid soils, probably due tohigher bacterial populations.

Dictyostelium aureo-stipes var. helvetium is an indicator species for coniferous forest.Other characteristic species are D. sep ten trionalis, and D. microsporum. Dictyosteliumfasciculatum, D. polycarpum, P. candidum and D. aureo-stipes var. aureo-stipes are char-acteristic of deciduous forest with neutral or alkaline mull humus. Dictyostelium minutumis characteristic of deciduous forest with acid humus.

Dictyostelium mucoroides S-type is dominant in most forests of Germany regardlessof forest or humus type although it appears to be most prevalent in deciduous forest withmull humus and neutral or alkaline pH. Polysphondylium violaceum and Dictyosteliumminutum may also dominate dictyostelid populations, the former in coniferous forest andthe latter in deciduous forest with acid humus.

The two sites with greatest species richness, Kaiserstuhl in the Black Forest regionand Rothenburg on the Tauber river in central Germany, had mull humus with slightlyalkaline pH. Yet two other sites with alkaline soil, Barbarossahohle south of the Harzmountains in the former East Germany and Wonsee in the Friinkische Schweiz moun-tains, had low species richness. These sites appeared to have experienced greater anthro-pogenic disturbances.

The highest numbers per gram were found in the Rothaargebirge near Siegen, a mixedforest with acid humus. This forest had species characteristic of both acid coniferous andalkaline deciduous forest. Because of the high density and diversity of its dictyostelidpopulations this forest should be investigated further for other species.

The lowest numbers per gram « 100) were in soils of four coniferous forests (spruceor pine) with acid humus. Again, this is most likely due to the lower densities of bacteriain mor humus.

The authors wish to thank Dr. Hiramitsu Hagiwara for examination of some of the isolates(ME-!, ME-2, TH-2, HE-4) and Kent Bares for assistance in collection of samples.

References

Brefeld O. 1869. Dictyostelium mucoroides. Ein neuer Organismus aus der Verwandtschaft derMyxomyceten. Abh. Seckenberg. Naturforsch. Ges. 7: 85-107.

-1884. Polysphondylium violaceum und Dictyostelium mucoroides nebst Bemerkungen zur Syste-matik der Schleimpilze. Unters. gesamtgeb. Mykol. 6: 1-34.

Cavender J. C. 1969. The occurrence and distribution of Acrasieae in forest soils. I. Europe. Amer.J. Bot. 56: 989-992.

Cavender J. C. and Raper K. B. 1965. The Acrasieae in nature. I. Isolation. Amer. J. Bot. 52:294-296.

Ellenberg H. 1988. Vegetation Ecology of Central Europe. Cambridge University Press, Cambridge,England. 4th ed. 731 p.

Hagiwara H. 1984. Review of Dictyostelium mucoroides Brefeld and D. sphaerocephalum (Oud.)Sacco et March. Bull. Nat. Sci Museum, Tokyo. Series B-10: 27-41.

-1989. The Taxonomic Study of Japanese Dictyostelid Cellular Slime Molds. Nat. Sci Museum,Tokyo. 131 p.

Leitner A. 1987. Acrasiales in geschiidigten Wiildern. Staatsexamensarbeit. Universitiit Konstanz.91 p. -

Oehler R. 1922. Demonstration: Dictyostelium mucoroides (Brefeld). Centralblatt f. Bakt. undParasitol. 89: 155-156.


Raper K. B. 1984. The Dictyostelids. Princeton University Press. Princeton, N.J. 453 p.Traub F. 1972. Acrasiales in Schweizer Wiildern. M.S. Thesis. Univ. of Zurich, Switzerland. 76 p.Traub F., Hohl H. R., and Cavender J. C. 1981 a. Cellular slime molds of Switzerland. I. Description

of new species. Amer. J. Bot. 68: 162-171.-1981 b. Cellular slime molds of Switzerland. II. Distribution in forest soils. Amer. J. Bot. 68:

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Ecological distribution of cellular slime molds in forest ...€¦ · Bot Relv 105: 199-219 0253-1453/95/020199-21 $1.50+0.20/0 @ 1995 Birkhiiuser Verlag, Basel Ecological distribution

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