A secondary structure attached to a main organ (e.g., hairs, stipules, tendrils).

Flattened or pressed closely against a surface (e.g., leaves growing horizontally).

Positioned side by side or in close proximity (e.g., leaves arranged oppositely on a stem).

Pressed closely against a surface but not fused (e.g., hairs or leaves lying flat).

Positioned close together (contrasts with remote, meaning widely spaced).

A solution of ammonia in water, sometimes used in horticulture as a nitrogen source or pH adjuster.

Growing or living in water; adapted to aquatic environments.

Aquatic plants that grow with their roots submerged but stems and leaves above water surface.

Plants that float on water surface, either free-floating or rooted with floating leaves.

Plants that grow entirely underwater, though may have flowers that emerge.