Inflorescences, Fruits and Seeds So many, many terms… So little time…

Inflorescences, Inflorescences, Fruits and SeedsFruits and SeedsSo many, many terms…So many, many terms…

So little time…So little time…

InflorescenceInflorescence

An inflorescence can be defined as the An inflorescence can be defined as the shoot system which serves for the shoot system which serves for the formation of flowers and which is formation of flowers and which is modified accordingly. modified accordingly.

The inflorescence form and position is The inflorescence form and position is important in routine identification as well important in routine identification as well as in the determination of phylogenetic as in the determination of phylogenetic relationships. relationships.

Inflorescence TypesInflorescence Types

Two quite different inflorescence types Two quite different inflorescence types occur in angiosperms. These are:occur in angiosperms. These are:

Determinate (monotelic) inflorescencesDeterminate (monotelic) inflorescences Indeterminate (polytelic) inflorescencesIndeterminate (polytelic) inflorescences

Determinate Determinate InflorescenceInflorescence

The main axis of the inflorescence ends The main axis of the inflorescence ends in a flower.in a flower.

The flowering sequence of a determinate The flowering sequence of a determinate inflorescence usually begins with the inflorescence usually begins with the terminal flower at the top of the cluster.terminal flower at the top of the cluster.

Determinate inflorescences are generally Determinate inflorescences are generally ancestral to indeterminate ones.ancestral to indeterminate ones.

Indeterminate Indeterminate FlorescenceFlorescence

The growing point produces only lateral The growing point produces only lateral flowers or partial inflorescences (groups flowers or partial inflorescences (groups of flowers).of flowers).

The flowering sequence usually starts at The flowering sequence usually starts at the base (or outside) of the cluster.the base (or outside) of the cluster.

Diagramatic Diagramatic RepresentationRepresentation

Determinate Determinate Inflorescenses Inflorescenses

The circles represent flowers and their The circles represent flowers and their sequence of opening (from large to small).sequence of opening (from large to small).

Determinate Determinate InflorescencesInflorescences

Cymes are one of the most common Cymes are one of the most common types of determinate inflorescences.types of determinate inflorescences.

The lateral branches of cymes are The lateral branches of cymes are composed of usually numerous, three-composed of usually numerous, three-flowered units usually showing opposite flowered units usually showing opposite branching.branching.

Types of CymesTypes of Cymes

Some Common Kinds of Some Common Kinds of Indeterminate Indeterminate InflorescencesInflorescences

The circles indicate flowers; their size indicates The circles indicate flowers; their size indicates the sequence of opening (from large to small).the sequence of opening (from large to small).

Racemes and SpikesRacemes and SpikesIndeterminate InflorescenceIndeterminate Inflorescence

A raceme is an inflorescence with a A raceme is an inflorescence with a single axis bearing flowers with pedicels.single axis bearing flowers with pedicels.

A spike is similar to a raceme but the A spike is similar to a raceme but the flowers are sessile (lacking a pedicel or flowers are sessile (lacking a pedicel or stalk). stalk).

Raceme ExampleRaceme Example

Spike ExampleSpike Example

Corymbs and PaniclesCorymbs and PaniclesIndeterminate InflorescenceIndeterminate Inflorescence

A corymb is a raceme with the pedicels A corymb is a raceme with the pedicels of the lowermost flowers elongated, of the lowermost flowers elongated, bringing all of the flowers to the bringing all of the flowers to the approximate same levelapproximate same level

A panicle is merely a compound raceme, A panicle is merely a compound raceme, that has two or more orders of branches, that has two or more orders of branches, with each axis bearing flowers or higher-with each axis bearing flowers or higher-order axes.order axes.

Corymb ExampleCorymb Example

Panicle ExamplePanicle Example

Head or capitulumHead or capitulum

A head (or capitulum) is a dense terminal A head (or capitulum) is a dense terminal cluster of sessile flowers. cluster of sessile flowers.

In a determinate head, the central flowers In a determinate head, the central flowers open first.open first.

In an indeterminate head, the peripheral In an indeterminate head, the peripheral (outermost) flowers open first.(outermost) flowers open first.

Helianthus annuusHelianthus annuus

UmbelUmbel

An umbel is an inflorescence in which all of the An umbel is an inflorescence in which all of the flowers often have pedicels of approximately flowers often have pedicels of approximately equal length that arise from a single region at equal length that arise from a single region at the apex of the inflorescence axis. the apex of the inflorescence axis.

Umbels are determinate if the flowers open Umbels are determinate if the flowers open from the center first and then proceed to the from the center first and then proceed to the periphery.periphery.

Umbels are indeterminate if the flowers open Umbels are indeterminate if the flowers open from the periphery first and then proceed to the from the periphery first and then proceed to the center. center.

Umbel ExampleUmbel Example

Umbel Example IIUmbel Example II

More on inflorescencesMore on inflorescences

Simple inflorescences have only a single Simple inflorescences have only a single axis (one order of branching).axis (one order of branching).

Compound inflorescences have two or Compound inflorescences have two or more orders of branching. more orders of branching.

Catkin or AmentCatkin or Ament

Any elongated Any elongated inflorescence inflorescence composed of composed of numerous numerous inconspicuous, inconspicuous, usually wind usually wind pollinated flowers. pollinated flowers. Willows have catkins. Willows have catkins.

Epiphyllous FlowersEpiphyllous Flowers

Some flowers are borne on leaves.Some flowers are borne on leaves.

Cauliflorous FlowersCauliflorous Flowers

Some flowers are borne on older stems or Some flowers are borne on older stems or trunks.trunks.

TendrilsTendrils

Inflorescences are sometimes modified for Inflorescences are sometimes modified for climbing by becoming elongated and twining or climbing by becoming elongated and twining or developing adhesive pads, thus forming developing adhesive pads, thus forming tendrils.tendrils.

FruitFruit

A fruit is a matured ovary along with fused A fruit is a matured ovary along with fused accessory structures (hypanthium or perianth accessory structures (hypanthium or perianth parts). parts).

There is great diversity of size, form, texture, There is great diversity of size, form, texture, means of opening, and anatomy among fruits.means of opening, and anatomy among fruits.

Many structures that a botanist considers to be Many structures that a botanist considers to be fruits are neither sweet nor good to eat!fruits are neither sweet nor good to eat!

Seed dispersal is the primary function of fruits.Seed dispersal is the primary function of fruits.

Parts of the FruitParts of the Fruit

PericarpPericarpaka ovary wallaka ovary wall

In some fruits, the pericarp becomes very In some fruits, the pericarp becomes very juicy as it matures. Often, such a fruit juicy as it matures. Often, such a fruit has a high sugar content and is readily has a high sugar content and is readily consumed by animals.consumed by animals.

The pericarp in many other plants dries The pericarp in many other plants dries as it matures. as it matures.

PericarpPericarp

Often, the pericarp is Often, the pericarp is dehiscentdehiscent, splitting , splitting open and releasing the seeds that it open and releasing the seeds that it contains.contains.

In other plants, the fruit is In other plants, the fruit is indehiscentindehiscent; ; the seeds remain enclosed within the seeds remain enclosed within pericarp tissue.pericarp tissue.

PericarpPericarp

The pericarp is often differentiated into layers, The pericarp is often differentiated into layers, particularly in fleshy fruits. particularly in fleshy fruits.

The The exocarpexocarp is the outer skinlike layer. is the outer skinlike layer. The The mesocarpmesocarp is the middle layer that often is the middle layer that often

becomes soft and fleshy.becomes soft and fleshy. Only certain kinds of fruit have a third layer, the Only certain kinds of fruit have a third layer, the

endocarpendocarp. This innermost layer closely . This innermost layer closely surrounds the seed or seeds. (ie hard pit of surrounds the seed or seeds. (ie hard pit of olive or papery apple core).olive or papery apple core).

A tomato is a fleshy fruit that does not have A tomato is a fleshy fruit that does not have endocarp.endocarp.

Simple FruitsSimple Fruits

Simple fruits result from a single flower.Simple fruits result from a single flower. Simple fruits are divided into 2 Simple fruits are divided into 2

categories.categories. 1) Those formed from a single carpel or 1) Those formed from a single carpel or

several fused carpels.several fused carpels. 2) Those formed from several separate 2) Those formed from several separate

carpels of a single gynoecium (aggregate carpels of a single gynoecium (aggregate fruits).fruits).

Common Types of Simple Common Types of Simple FruitFruit

Fruit fleshy at maturity:Fruit fleshy at maturity: BerryBerry – entire pericarp soft; generally – entire pericarp soft; generally

with two or more seeds. Derived from with two or more seeds. Derived from either superior or inferior ovaries. either superior or inferior ovaries. Examples: tomato, banana, and grape. Examples: tomato, banana, and grape. Includes the pome, the pepo, and the Includes the pome, the pepo, and the hesperidium.hesperidium.

Fruit Types associated Fruit Types associated with Berrieswith Berries

PomePome – Derived from an inferior ovary and surrounded – Derived from an inferior ovary and surrounded by a fleshy hypanthium. Restricted to the Rosaceae by a fleshy hypanthium. Restricted to the Rosaceae subfamily Maloideae. Examples: pear, apple, and subfamily Maloideae. Examples: pear, apple, and quince.quince.

PepoPepo – Derived from an inferior ovary with a leathery – Derived from an inferior ovary with a leathery rind. Generally restricted to Cucurbiaceae family rind. Generally restricted to Cucurbiaceae family (watermelon, pumpkin, cucumber).(watermelon, pumpkin, cucumber).

HesperidiumHesperidium – Derived from a superior ovary with a – Derived from a superior ovary with a leather pericarp having oil glands. The carpels are leather pericarp having oil glands. The carpels are easily separated as segments that are lined with fleshy easily separated as segments that are lined with fleshy hairs. Restricted to Citrus and its close relatives hairs. Restricted to Citrus and its close relatives (Rutaceae). Oranges, lemons, grapefruit.(Rutaceae). Oranges, lemons, grapefruit.

Common Types of Simple Common Types of Simple FruitFruit

Fruits fleshy at maturity.Fruits fleshy at maturity. DrupeDrupe – Pericarp distinguishable as – Pericarp distinguishable as

three layers: exocarp, mesocarp, and three layers: exocarp, mesocarp, and endocarp. The endocarp is a ‘stone’ that endocarp. The endocarp is a ‘stone’ that encloses the seed. Examples: peach, encloses the seed. Examples: peach, plum, cherry, coconut, olive.plum, cherry, coconut, olive.

Common Types of Simple Common Types of Simple FruitFruit

Fruit dry, one-seeded, not breaking apart Fruit dry, one-seeded, not breaking apart at maturity.at maturity.

Achene – Achene – Extremely variable in form. Extremely variable in form. Seed and pericarp attached only by the Seed and pericarp attached only by the funiculus (ovule stalk). Examples: funiculus (ovule stalk). Examples: buttercup, buckwheat. Includes also buttercup, buckwheat. Includes also samara, cysella, and utricle.samara, cysella, and utricle.

SamaraSamara – A winged achene. Examples – A winged achene. Examples are elm, ash, and birch.are elm, ash, and birch.

CypsellaCypsella – An achene with adnate calyx – An achene with adnate calyx (pappus) Examples: members of the (pappus) Examples: members of the Asteraceae family such as the dandelion.Asteraceae family such as the dandelion.

UtricleUtricle – A bladdery achene with the wall – A bladdery achene with the wall loosely surrounding the seed. Example: loosely surrounding the seed. Example: pigweed.pigweed.

Common Types of Simple Common Types of Simple FruitFruit

Fruit dry, one-seeded, not breaking apart Fruit dry, one-seeded, not breaking apart at maturity.at maturity.

CaryopsisCaryopsis – Seed coat and pericarp – Seed coat and pericarp completely adnate. Restricted to completely adnate. Restricted to Poaceae family. Examples: maize, Poaceae family. Examples: maize, wheat, rye, barely, sorghum.wheat, rye, barely, sorghum.

Common Types of Simple Common Types of Simple FruitFruit

Fruit dry, one-seeded, not breaking apart Fruit dry, one-seeded, not breaking apart at maturity.at maturity.

NutNut - Exocarp hard; the fruit often - Exocarp hard; the fruit often subtended by an involucre (whorl of subtended by an involucre (whorl of bracts). Derived from a syncarpous bracts). Derived from a syncarpous synoecium, but one-seeded by abortion synoecium, but one-seeded by abortion of ovules. Examples: acorn, filbert.of ovules. Examples: acorn, filbert.

Common Types of Simple Common Types of Simple FruitFruit

Fruit fleshy or dry, at maturity breaking into Fruit fleshy or dry, at maturity breaking into one- or a few-seeded segments, the seeds one- or a few-seeded segments, the seeds remain completely surrounded by the pericarp.remain completely surrounded by the pericarp.

SchizocarpSchizocarp – Fruit breaking into one- – Fruit breaking into one-carpellate segments (mericarps). Examples: carpellate segments (mericarps). Examples: members of the Apiaceae such as fennel and members of the Apiaceae such as fennel and dill, and others such as hollyhock. Schizocarps dill, and others such as hollyhock. Schizocarps may be winged (samaroid schizocarps) as in may be winged (samaroid schizocarps) as in maple or fleshy as in madder.maple or fleshy as in madder.

Common Types of Simple Common Types of Simple FruitFruit

Fruit fleshy or dry, at maturity breaking Fruit fleshy or dry, at maturity breaking into one- or a few-seeded segments, the into one- or a few-seeded segments, the seeds remain completely surrounded by seeds remain completely surrounded by the pericarp.the pericarp.

NutletNutlet – Friut deeply four-lobed, breaking – Friut deeply four-lobed, breaking into one-seeded half-carpellate into one-seeded half-carpellate segments; used especially for fruits of segments; used especially for fruits of borage, vervain, and mint families. borage, vervain, and mint families. Examples: sage, borage.Examples: sage, borage.

Common Types of Simple Common Types of Simple FruitFruit

Fruit dry at maturity dehiscing either Fruit dry at maturity dehiscing either lengthwise, or by pores, teeth or a lid and lengthwise, or by pores, teeth or a lid and exposing the seeds.exposing the seeds.

CapsuleCapsule – Syncarpous and typically – Syncarpous and typically several- to many-seeded. Perhaps the several- to many-seeded. Perhaps the most common and certainly the most most common and certainly the most variable of dehiscent fruits.variable of dehiscent fruits.

Septicidal capsuleSepticidal capsule – Opens lengthwise – Opens lengthwise along the septa. Example: zigadene.along the septa. Example: zigadene.

Loculicidal capsuleLoculicidal capsule – Opens lengthwise – Opens lengthwise between the septa and directly into the between the septa and directly into the locule (evening primrose and iris).locule (evening primrose and iris).

Poricidal capsulePoricidal capsule – Opens by pores – Opens by pores near the top (poppy)near the top (poppy)

Schizocarpic capsuleSchizocarpic capsule – Breaks – Breaks completely apart at the septa into one-completely apart at the septa into one-seeded segments (castor bean).seeded segments (castor bean).

Denticidal capsuleDenticidal capsule – Opens apically by – Opens apically by a ring of teeth (Eucalyptus, chickweed) a ring of teeth (Eucalyptus, chickweed)

Circumscissile capsuleCircumscissile capsule – Opens – Opens horizontally in a ring so that a lid is horizontally in a ring so that a lid is formed (purslane, plantain, portulaca)formed (purslane, plantain, portulaca)

Common Types of Simple Common Types of Simple FruitFruit

Fruit dry at maturity dehiscing either Fruit dry at maturity dehiscing either lengthwise, or by pores, teeth or a lid and lengthwise, or by pores, teeth or a lid and exposing the seeds.exposing the seeds.

SiliqueSilique – A long, narrow (more than – A long, narrow (more than twice as long as broad) 2-carpellate fruit twice as long as broad) 2-carpellate fruit whose outer walls break away from a whose outer walls break away from a central papery partition. Restricted to central papery partition. Restricted to Brassicaceae. Examples mustard, kale.Brassicaceae. Examples mustard, kale.

SiliqueSilique

Common Types of Simple Common Types of Simple FruitFruit

Fruit dry at maturity dehiscing either Fruit dry at maturity dehiscing either lengthwise, or by pores, teeth or a lid and lengthwise, or by pores, teeth or a lid and exposing the seeds.exposing the seeds.

FollicleFollicle – Unicarpellate, dehiscing along – Unicarpellate, dehiscing along one suture (Examples: milkweed, one suture (Examples: milkweed, larkspur).larkspur).

Milkweed FollicleMilkweed Follicle

Common Types of Simple Common Types of Simple FruitFruit

Fruit dry at maturity dehiscing either Fruit dry at maturity dehiscing either lengthwise, or by pores, teeth or a lid and lengthwise, or by pores, teeth or a lid and exposing the seeds.exposing the seeds.

Legume – Unicarpellate, dehiscing along Legume – Unicarpellate, dehiscing along two sutures. Restricted to the Fabaceae. two sutures. Restricted to the Fabaceae. Examples: Bean and pea. Examples: Bean and pea.

Simple Fruit Derived from Simple Fruit Derived from more than one ovary.more than one ovary.

Fruit derived from a flower with an Fruit derived from a flower with an apocarpous gynoecium.apocarpous gynoecium.

AggregateAggregate – The ovary of each carpel – The ovary of each carpel matures into one of the simple fruits matures into one of the simple fruits described previously. A raspberry is an described previously. A raspberry is an aggregate of small drupes. aggregate of small drupes.

Simple Fruit Derived from Simple Fruit Derived from more than one ovary.more than one ovary.

Fruit derived from a flower with an Fruit derived from a flower with an apocarpous gynoecium.apocarpous gynoecium.

AccessoryAccessory – Tissue other than or in – Tissue other than or in addition to the ovary enlarges and addition to the ovary enlarges and becomes fleshy. Examples: strawberry becomes fleshy. Examples: strawberry and blackberry in which the receptacle and blackberry in which the receptacle becomes fleshy. becomes fleshy.

Simple Fruit Derived from Simple Fruit Derived from more than one ovary. more than one ovary.

Fruit derived from a flower with an Fruit derived from a flower with an apocarpous gynoecium.apocarpous gynoecium.

Hip – The hypanthium of a perigynous Hip – The hypanthium of a perigynous flower enlarges and becomes fleshy at flower enlarges and becomes fleshy at maturity but does not become adherent maturity but does not become adherent to the carpels. Known only from certain to the carpels. Known only from certain Rosaceae, especially Rosa. The ovaries Rosaceae, especially Rosa. The ovaries usually mature into achenes. usually mature into achenes.

Simple Fruit Derived from Simple Fruit Derived from more than one ovary.more than one ovary.

Fruit derived from a flower with an Fruit derived from a flower with an apocarpous gynoecium.apocarpous gynoecium.

Multiple FruitMultiple Fruit

A multiple fruit is the product of the gynoecia of several A multiple fruit is the product of the gynoecia of several closely clustered flowers. closely clustered flowers.

The individual ovaries of each flower develop into one The individual ovaries of each flower develop into one of the simple fruits described previously. Accessory of the simple fruits described previously. Accessory tissue such as the calyx of the mulberry or the tissue such as the calyx of the mulberry or the inflorescence axis of the pineapple may become fleshy. inflorescence axis of the pineapple may become fleshy. The fruit appears to be ‘merged’ together. The fruit appears to be ‘merged’ together.

The synconium is a special kind of multiple fruit The synconium is a special kind of multiple fruit restricted to Ficus (fig) where the inflorescence axis restricted to Ficus (fig) where the inflorescence axis enlarges and surrounds the flowers and becomes enlarges and surrounds the flowers and becomes fleshy. The individual ovaries mature as achenes.fleshy. The individual ovaries mature as achenes.

SeedSeed

A seed is a matured ovule that contains A seed is a matured ovule that contains an embryo and often its nutritive tissues an embryo and often its nutritive tissues (endosperm, perisperm). (endosperm, perisperm).

The seed is surrounded by a seed coat.The seed is surrounded by a seed coat. Seeds may be variously sized and Seeds may be variously sized and

shaped. They may be associated with a shaped. They may be associated with a wing or tuft of hairs.wing or tuft of hairs.

EndospermEndosperm

Endosperm is a usually triploid tissue derived Endosperm is a usually triploid tissue derived from the union of the two nuclei in the central from the union of the two nuclei in the central cell of the female gametophyte. Endosperm cell of the female gametophyte. Endosperm may be homogeneous (uniform in texture) or may be homogeneous (uniform in texture) or ruminate (dissected by partitions that grow ruminate (dissected by partitions that grow inward from the seed coat).inward from the seed coat).

Endosperm may contain starch, oils, proteins, Endosperm may contain starch, oils, proteins, oligosaccharides, and/or hemicellulose.oligosaccharides, and/or hemicellulose.

Endosperm may be hard to soft and fleshy.Endosperm may be hard to soft and fleshy.

PerispermPerisperm

Perisperm is a specialized diploid Perisperm is a specialized diploid nutritive tissue derived from the nutritive tissue derived from the megasporangium. megasporangium.

Seed CoatSeed Coat

The testa (plural testae) of a seed coat The testa (plural testae) of a seed coat develops from the outer integument.develops from the outer integument.

The tegmen (plural tegmina) of a seed coat The tegmen (plural tegmina) of a seed coat develops from the inner integument.develops from the inner integument.

The testa varies in surface texture due to the The testa varies in surface texture due to the pattern and outgrowths of the individual cells pattern and outgrowths of the individual cells composing its surface. composing its surface.

The testa is sometimes colorful and fleshy. The testa is sometimes colorful and fleshy.

More on SeedsMore on Seeds

Some seeds are associated with a hard Some seeds are associated with a hard to soft, oily to fleshy, and often brightly to soft, oily to fleshy, and often brightly colored structre called an colored structre called an arilaril. .

An aril is usually an outgrowth of the An aril is usually an outgrowth of the funiculus or the outer integument.funiculus or the outer integument.

The seed bears a scar called the hilum The seed bears a scar called the hilum (plural hila) at the point where it was (plural hila) at the point where it was attached to the funiculus.attached to the funiculus.

Seed EmbryoSeed Embryo

The embryo consists of an epicotyl, a The embryo consists of an epicotyl, a radicle, a hypocotyl, and usually one or radicle, a hypocotyl, and usually one or two cotyledons (seedling leaves).two cotyledons (seedling leaves).

Seed Embryos ContinuedSeed Embryos Continued

The epicotyl develops into the shoot.The epicotyl develops into the shoot. The radicle develops into the primary root The radicle develops into the primary root

and usually gives rise to the root system.and usually gives rise to the root system. The hypocotyl connects the epicotyl and The hypocotyl connects the epicotyl and

radicle.radicle. The cotyledons (seedling leaves) may be The cotyledons (seedling leaves) may be

leaflike, fleshy, or modified as nutrient-leaflike, fleshy, or modified as nutrient-absorptive structures.absorptive structures.