Glossary

Aquatic Plant Identification

Alternate Leaves – leaves spaced singly along a stem, one at each node.

Axil – the angle between two structures on a plant, such as the notch created between the stem and the base of a leaf.

Blade – the expanded portion of a leaf, in contrast to the leaf stalk.

Bract – a reduced or modified leaf that is located just below a flower or flower stalk.

Canopy – a cluster of leaves and branching stems on or near the water surface.

Capsule – a dry fruit with more than one seed that opens at maturity.

Cuticle – the waxy protective layer on the surface of a leaf or stem.

Detritus – any disintegrated matter; debris, such as loose organic matter composed of parts of decaying plants.

Divided – a plant structure that is cut into distinct parts; often used to describe divisions of a leaf.

Entire – a leaf margin that is smooth, not toothed or lobed.

Epiphyte – a plant that grows on another plant, but does not take its food or water from that plant.

Fruit – a ripened ovary, along with any other structures that mature with it and form a unit.

Heterophylly – the presence of two different kinds of leaves on the same plant.

Keel – a sharp ridge.

Midrib – the central vein of a leaf that runs from its base to tip.

Node – the place on a stem where a leaf or branch arises.

Nutlet – a small, dry, one-seeded fruit with a hard wall.

Opposite leaves – leaves arranged along a stem in pairs, directly across from each other.

Ovary – the part of a flower’s female reproductive structure that encloses the seeds.

Petal – an inner floral leaf, usually colored.

Petiole – leaf stalk.

Rhizome – a creeping, underground stem.

Rosette – leaves arranged in a radiating pattern at the base of a plant.

Serrate – a sharply toothed leaf margin.

Sheath – the portion of a leaf that wraps around the stem.

Spike – flowers closely spaced on a single stalk.

Spore – A single-celled reproductive structure produced by non-flowering plants.

Stipule – an appendage of tissue on the stem at the base of a leaf stalk.

Stolon – a stem that creeps along the surface of the sediment or ground.

Tuber – the thickened portion of a rhizome, providing food-storage for the plant.

Turion – a specialized overwintering structure.

Whorl – an arrangement of leaves, bracts or flowers with three or more radiating from a common point.

Winter bud – A shortened branch with tightly spaced, often reduced leaves.  This structure survives the rest of the plant over winter and renews growth in the spring.