Plant Taxonomy: Angiosperms: Inflorescences and Fruit

Inflorescnece

A cluster of flowers on a branch or system of branches

Flower

The reproductive structure of a plant, often containing petals, stamens, and pistils

Pedicel

The small stalk that attaches a single flower to the main stem of the inflorescence

Bract

A modified leaf located at the base of a flower or inflorescence, sometimes resembling petals

Peduncle

The main stalk that supports the entire inflorescence or solitary flower

Determinate

The first flower to bloom is at the top

These inflorescences are called cymes

Indeterminate

The first flower to bloom is at the bottom

Raceme

Indeterminate inflorescence

Flowers are attached to the rachis by pedicles

Spike

Flowers are attached directly to the rachis

Indeterminate inflorescence

Catkin

A spike inflorescence with imperfect flowers of a single sex

Indeterminate inflorescence

Spadix

A spike in which the rachis is swollen and fleshy

Indeterminate inflorescence

Umbel

Flower pedicles are all attached at the same point on the peduncle or rachis

Indeterminate inflorescence

Capitulum

Disk and ray florets are arranged on a head to mimic a large flower

Indeterminate inflorescence

Disk florets

Florets in the middle of a capitulum and are radially symmetrical

Ray florets

Florets on the edge of a capitulum

mimic petals, are often very showy, and are bilaterally symmetrical

Seed

The fertilized ovule that contains the embryo of a new plant

Pericarp

The part of a fruit formed from the ovary wall

Surrounds and protects the seed(s)

Exocarp

Outermost layer of the pericarp

Often forms the skin of the fruit

Mesocarp

Middle layer of the pericarp

Usually the fleshy or juicy part of the fruit

Endocarp

Innermost layer of the pericarp

Directly surrounds the seed(s)

May be hard or soft

Skin

Outer covering of the fruit

Typically referring to the exocarp when it is tough or noticeable

Simple fruit

Derived from one flower with a single or syncarpous pistil

Aggregate fruit

Derived from one flower with multiple pistils

Multiple fruit

Derived from multiple flowers on a single axis

Accessory fruit

Derived from a flower part other than the pistil

Fleshy fruit

Pericarp soft and juicy when ripe

Dry fruit

Pericarp hard or papery when ripe

Dehiscent fruit

Splits open when ripe

Indehiscent fruit

Does not split open when ripe

Types of simple fruit

Simple fleshy fruit

Simple, dry, indehiscent fruit

Simple, dry, dehiscent fruit

Berry

Simple, fleshy fruit

Exocarp and fleshy endocarp

Drupe

Simple, fleshy fruit

Stony, hardend endocarps, often called “pits”, that surrounds and protects te seed, surrounded by a fleshy mesocarp

Pepo

Simple, fleshy fruit

Fleshy mesocarp and leathery exocarp

Hesperidium

Simple, fleshy fruit

Juice sacs divided by septum with a leathery outer pericarp

Achene

Simple, dry, indehescent fruit

Hardened pericarp surrounding an unattached seed

Grain/Caryopsis

Simple, dry, indehiscent fruit

Seed fused to pericarp

Utricle

Simple, dry, indehiscent fruit

Pericarp is inflated at maturity, resulting in a large locule

Samara

Simple, dry, indehiscent fruit

Winged fruit containing a seed

Nut

Simple, dry, indehiscent fruit

Hardened, thick pericarp surrounding an unattached seed

Follicle

Simple, dry, dehiscent fruit

One line of dehiscence

Legume

Simple, dry, dehiscent fruit

Two lines of dehiscence

Silique

Simple, dry, dehiscent fruit

Two lines of dehiscence, leaves behind a replum, longer than wide

Silicle

Simple, dry, dehiscent fruit

Two lines of dehiscence, leaves behind a replum, wider than long

Capsules

Simple, dry, dehiscent fruit

Develop from flowers with syncarpous pistils

Loculicidal, poricidal, septicidal

Loculicidal capsule

Simple, dry, dehiscent fruit

Splits in the middle of the locule, or cavity

Poricidal capsule

Simple, dry, dehiscent fruit

Small openings on the top or side

Septicidal capsule

Simple, dry, dehiscent fruit

splits along a septum

Placentation

The arrangement of ovule in the ovary

Axile, basal, free-central, marginal, parietal

Axile placentation

Ovules attached to the central axis of ovary with two or more locules

Basal placentation

Ovule positioned at the base of a single-loculed ovary

Free-central placentation

Ovules attached to a free-standing column in the center of a single-locule ovary

Marginal placentation

Ovules attached to the juxtaposed margins of a simple pistil

Parietal placentation

Ovules attached to the walls of the ovary