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.

Back to Top