Choose from the categories below to help define a term:
- Woody: With hard (lignified) tissues that will retain their shape long after death.
- Herbaceous: With soft tissues that collapse soon after death.
- Perennial: Living more than two years.
- Biennial: Normally living two years.
- Annual: Normally living only one year. Winter annuals germinate in the autumn and mature and die the next spring or summer.
- Tendril: An elongated twining segment of a leaf or branch, usually supporting the stem.
- Lenticel: A portion of the cork layer in the bark of stems where the cells are loose, allowing exchange of gases. Usually they are raised and they may be a different color from the rest of the bark.
- Rhizome: A horizontal underground stem. Rhizomes produce stems above ground at
intervals, as in sod-forming grasses, bracken fern, and others.
- Stolon or Runner:
Similar to a rhizome (being a stem), but located on or near the soil surface.
A leaf has a bud in its axil (at the angle between the leaf-stalk and the stem), whereas a
leaflet has no bud at its base. This is a way to distinguish a leaf from a leaflet.
- Simple Leaf:
A leaf in which the blade is all one unit.
- Compound Leaf:
A leaf in which the blade is composed of separate parts, each part called a
leaflet. Decompound means more than once compound.
- Alternate: Only one leaf arising at a node.
Two leaves arising at a node.
- Whorled: More than two leaves arising at a node.
- Sessile: Without a petiole or leaf-stalk, that is, the blade is attached directly to the stem.
The contrasting condition is
- Pinnate: Arranged like a feather, with the parts arising along a central axis.
- Palmate: Arranged like the fingers arising from the palm of the hand, with the several parts all attached to one point.
- Glabrous: Without hairs on the surface.
- Pubescent: With hairs. There are various kinds of pubescence, differing in the stiffness,
length, and density of the hairs (villous, hirsute, hispid, tomentose, etc.)
- Stipule: One of a pair of appendages sometimes present at the base of a leaf-stalk.
Of or pertaining to the stem. Cauline leaves are those borne on the stems above the soil surface.
Arising from the stem at or below the ground surface only.
- Pistil: The ovule-bearing or seed-bearing organ of a flower, consisting, when complete, of ovary, style and stigma.
- Stamen: The pollen-bearing organ of a flower, of a flower, consisting of the filament and
- Ovary: The enlarged lower part of the pistil, enclosing the ovules or young seeds.
- Style: A narrow, usually of cylindrical and more or less filiform extension of the ovary, which, when present, bears the stigma at its apex.
- Stigma: That part of a pistil which receives the pollen.
- Anther: The pollen-bearing part of a stamen.
- Carpel: A simple pistil or a single member of a compound pistil; regarded as a modified leaf.
- Bisexual or Perfect:
With both stamens and pistils.
- Unisexual: With either stamens (staminate flower) or pistils (pistillate flower), but not both.
- Monoecious Plant:
Flowers unisexual but with both kinds of flowers on one individual plant.
- Dioecious Plant:
Flowers unisexual but with only one sex per individual plant.
- Bract: A reduced (smaller than normal sized) leaf at the base of a flower-stalk. If the
flower-stalk is short or absent the bract or bracts may be at the base of a flower and
Loose, diversely branching flower cluster.
- Berry: A fleshy fruit having numerous seeds embedded in the flesh (tomato, Solanum,
- Capsule: A dry, many-seeded fruit derived from more than one carpel, splitting open at
maturity. Capsules often have several chambers (Ricinus, Agrostemma).
- Follicle: A dry fruit derived from only one carpel which splits open on one side at
maturity. Follicles have one chamber and many seeds (Asclepias, Apocynum).
- Legume or Pod:
The fruit of members of the family Leguminosae. One chambered,
normally splitting on both edges, enclosing a row of seeds (garden peas and beans, Cassia,
Copyright © 2002
|University of Pennsylvania
Created by: Alexander Chan (2003), Daphne Downs
Chris Tsai (2001),
Brett Begley (2000),
Janet Triplett (1997)
|Faculty Advisor: Dr. Robert