corolla

calyx

Parts of a Flower

Floral Symmetry

Actinomorphic Zygomorphic

Inferior SuperiorHalf-Inferior

• Complete Flower -has pistil, stamens, petals and sepals• Incomplete Flower –if any one of these parts is missing

• Perfect Flower - has pistil, stamens – may lack petals and sepals• Imperfect Flower - either pistil or stamen absents

The stamen and pistil are the essential parts of a flower and are involved in seed production

Inflorescence Types• Spike - an elongate, unbranched, indeterminate inflorescence with sessile

flowers.• Spikelet - a small spike, characteristic of grasses and sedges.• Raceme - an elongate, unbranched, indeterminate inflorescence with

pedicelled flowers.• Panicle - a branched raceme.• Corymb - a flat-topped raceme with elongate pedicels reaching the same

level.• Compound Corymb - a branched corymb.• Umbel - a flat-topped or rounded inflorescence with the pedicels originating

from a common point. Umbels can be determinate or indeterminate.• Compound Umbel - a branched umbel, with primary rays arising from a

common point, and    secondary umbels arising from the tip of the primary rays.

• Capitulum - (or head)a dense vertically compressed inflorescence with sessile flowers on a receptacle and subtended by an involucre of phyllaries, characteristic of the Asteraceae. Heads can be determinate or indeterminate.

• Thyrse - a many-flowered inflorescence with an indeterminate central axis and many opposite, lateral dichasia; a mixed inflorescence, with determinate and indeterminate shoots.

Inflorescence Types

• Simple Cyme or Dichasium - a determinate inflorescence with 2 dichotomous lateral branches and pedicles of equal length.

• Compound Dichasium - a branched dichasium.• Compound Cymea - determinate thyrse.• Helicoid Cyme (or bostryx) - a determinate cyme in

which the branches develop only on 1 side, due to the abortion of opposing paired bud, the inflorescence thus appearing simple.

• Cincinnus - a tight, modified helicoid cyme in which the pedicels are very short.

• Scorpioid Cyme (or rhipidium) - a zig-zag determinate cyme with branches developing alternately on opposite sides of the rachis, due to abortion of opposing paired bud.

Flowers are the Reproductive Structures of the Angiosperms

Pollination

Fertilization

Pollination Syndromes

Pollination Syndromes in Modern Flowers

• Beetle• Carrion Fly • Bee• Butterfly/Moth• Bat • Bird

• Wind

Beetles: Beetle-pollinated flowers are usually flat or shaped like a shallow bowl (easily accessible). The anthers and stigma are exposed. The pollen or nectar is easily accessible. The flowers have a dull greenish or off-white color and a strong fruity or putrid odor.

Beetle Pollination

Carrion and Dung Flies: The anthers and stigma are hidden. The flowers lack nectar; have a dull greenish, brownish, or purplish color; and have a strong odor of decaying protein. (Note that other flies visit different types of flowers, and several fly families actually mimic bees.)

Fly Pollination

Bees: Bee-pollinated flowers usually have an intricate shape, and strength and dexterity are often required to enter. The anthers and stigma are usually hidden. The flowers produce moderate amounts of nectar that is hidden (but there may be patterned nectar guides, visible in either ambient or ultraviolet light). The flowers are blue, violet, or yellow, with a weak but pleasant odor.

Butterflies and Moths: Butterfly and moth-pollinated flowers are often tubular or funnel-shaped, with nectar at the base. The length of the tube may be correlated with the length of the arthropods proboscis. The flower often has some sort of landing platform. Butterfly flowers can be yellow, blue, violet, or red and often lack a strong odor. Moth flowers are nocturnal, often with a white or drab color and a sweet scent.

Bats: Bat-pollinated flowers are nocturnal. They have an easily accessible position away from the leaves or may appear before the leaves develop. The flowers may be either large and cup-shaped or "brushlike," with many exposed stamens. They produce large amounts of both pollen and nectar, and they have a dull color and a strong, sometimes unpleasant odor.

Hummingbirds: Hummingbird-pollinated flowers are tubular, and the length of the tube may be precisely correlated with the length of the pollinator bill. They produce large amounts of nectar available at the base of the tube, have a red color, and lack an odor.

Wind: Wind-pollinated flowers often appear before the leaves develop. The flowers are exposed, reduced, and inconspicuous. The anthers and stigmas are exposed. The anthers often dangle from their filaments and produce large amounts of pollen; the stigmas are often long and feathery; the flowers lack an odor.

Pollination

Fertilization

A fruit develops from the ovary wall after fertilization of the egg in the ovule

A seed develops from the ovule after fertilization of the egg in the ovule

Simple Fruit

Simple fruit

pericarp

Pea - Legume

pericarpseed inside

Maple - Samara

PericarpExocarpMesocarpEndocarp

Nectarine - Drupe

Pumpkin - Pepo

Blackberry

Blackberry

Multiple Fruit

Multiple Fruit

Mullberry

Pineapple

Pineapple

Osage orange

Simple Accessory Fruit

Apple - Pome

Aggregate Accessory Fruit