San Diego Natural History Museum--Your Nature ConnectionSDNHM Field Guide

Glossary of Plant Terms

Androdioecious
Said of a plant species that has individuals with perfect flowers and individuals with staminate flowers.
Areole
A generally circular cluster of spines on members of the cactus family.
Aril
A special covering for seeds that develops from the seed stalk. It's often brightly colored, and serves as a signal for seed dispersers.
Bract
A leaf associated with the flowers or inflorescence of a plant. Bracts may be similar to the other leaves on the plant or may be modified in appearance.
Deciduous
To fall off or shed seasonally; usually refers to the leaves of a plant.
Dioecious
Said of a plant species which has some individuals which bear only staminate flowers, and some which bear only pistillate flowers, and there are no perfect flowers. These are the species that are commonly referred to as having male and female plants.
Endemic
Belonging or native to a particular people or country.
Glabrous
Having a surface without hairs or projections; smooth.
Gynodioecious
Said of a plant species that has individuals with perfect flowers and individuals with pistillate flowers.
Involucre
A whorl of bracts, often cup-like, at the base of a flower or cluster of flowers.
Lanceolate
Shaped like a lance head, that is, tapering to a point at the apex and at the base.
Lenticel
A loose group of cells that penetrates the surface, such as the stem, of a woody plant. Gases are exchanged between the atmosphere and the underlying tissues through these cells.
Monoecious
Said of a plant species in which all individuals bear both staminate and pistillate flowers, but there are no perfect flowers. For example, oaks—with male flowers in catkins, producing wind-borne pollen, and female flowers on the stems, producing acorns.
Obovate
Shaped like an egg, with the narrow end at the base.
Palmate
Resembling a hand with the fingers outspread.
Perfect flowers
Perfect (also called bisexual) flowers have both functional male parts (stamens or anthers capable of producing pollen) and functional female parts (pistil or ovary capable of producing seeds).
Petiole
Slender stem supporting the blade of a foliage leaf.
Pinnate
With leaflets arranged on both sides of a common axis, like a feather.
Pistillate
Pistillate (or "female") flowers are ones which have a functional pistil, capable of producing seeds—but either have no stamens at all, or have stamens with anthers that are incapable of producing pollen.
Pneumatophores
Roots that function as respiratory organs in wetland plants.
Propagule
A structure, such as a cutting, seed, or spore, that propagates a plant.
Sessile
Permanently attached; not freely moving.
Staminate
Staminate (or "male") flowers are ones which have functional stamens, capable of producing pollen—but either have no ovary at all, or an ovary which is not fertile.
Sterile
Not capable of reproducing. Sterile flowers may have petals and sepals, but no funtional reproductive parts at all.
Trioecious
Said of a plant species that has individuals with staminate flowers, individuals with pistillate flowers, and individuals with perfect flowers.
Whorl
Three or more leaves or other structures surrounding a stem at the same point.