Glossary

Alternate
Referring to the arrangement of plant parts, usually leaves; leaves are alternate when they appears one per stem node, as opposed to opposite in which two leaves appear per stem node.
Annual
Plants complete their life cycle in a single year and survive the winter as seeds.
Axil or axis
The upper angle a leaf makes with the stem; the bud found in that angle is an axillary bud.
Blade
The flat, enlarged part of a leaf
Compound
Consisting of two or more similar part, as in leaflets that form a compound leaf, or referring to a branched inflorescence with stalked flowers.
Emersed
Emergent, normally found above the surface of the water with a stiff or rigid stem.
Filaments
A thread- or hair-like structure.
Florets
one of the small flowers in an inflorescence, as in spikelet of a grass.
Fragmentations
Breaking apart forming fragments or pieces.
Midrib
The central vein of a leaf.
Node
Stem area (or joint) from which a leaf or leaves, branch or branches originate.
Opposite
Referring to the arrangement of plant parts, usually leaves; leaves are opposite if they appear two per stem node.
Perennial
Living more than two years.
Petal
the showy, often brightly colored part of a flower; a part of the corolla of a flower.
Petiole
The stalk of a leaf.
Rhizome
A horizontal underground stem different from the roots because it has nodes from which new leaves or stems branch. Rhizomes often store food for the plants.
Sepal
One of the individual flower parts of the calyx; usually green.
Sheath
A tubular, surrounding or enveloping structure.
Spike
A simple long inflorescence with flowers as in the spikes of pondweeeds or pickerelweed.
Spikelet
A small spike of sessile flower, being only bracted, and considerably reduced in size; characteristics of grasses and sedges.
Stolon
A horizontal runner; a specialized stem with long internodes, capable of rooting at the nodes to establish new plants; means of vegetative propagation (e.g. tape grass).
Submersed
Normally growing underwater; a plant may grow totally underwater or may have some parts emersed. Stems are usually soft or flacid.
Toothed
Having sharp teeth along the margins as in hydrilla or naiad leaves.
Tuber
A fleshy or enlarged stolon as in hydrilla.
Vein
Conducting tubes or channels in a plant that are used to move water, food and minerals; veins are obvious lines on the surface of leaves.
Whorl
A circular or ring arrangement of three or more structures like leave (e.g.coontail) or flowers.