Aerial: Occurring above ground or water.

Auricles: Earlike structures found at the junction of the blade and sheath; extensions of the leaf blade around the stem.

Awn: A narrow, hairlike bristle.

Axil: The position between the stem and a leaf.

Axillary: Positioned in or arising in an axil.

Basal rosette: Cluster of leaves radiating from the base of the stem at ground level.

Bract: A reduced leaf or leaflike structure at the base of a flower or flower cluster.

Bristle: A short, stiff hair or hairlike structure.

Collar: The area on the outside of a grass leaf at the junction of the blade and the sheath.

Cotyledon: A primary leaf of the embryo; a seed leaf.

Creeping roots: Thickened roots that store carbohydrates, spread vertically and horizontally in the soil and contain adventitious buds that give rise to new plants.

Disk flower: The central flowers of a flower head in the Asteraceae (aster family).

Disseminate: To disperse throughout.

Herbaceous: A non-woody plant with stems and leaves that die back to the ground in the winter.

Node: The position on the stem where leaves or branches originate.

Ocrea: A membranous, papery sheath around the stem at the nodes as in members of the Polygonaceae (smartweed family).

Palmate: Lobed, veined or divided from a common point, like the fingers of a hand.

Panicle: A flower cluster with a main axis and subdivided branches that is often pyramid-shaped.

Petiole: A leaf stalk.

Pinnate: The word used to describe a compound leaf with leaflets arranged on opposite sides of an elongated axis.

Prickle: A small, sharp outgrowth of the stem surface.

Ray flower: The straplike outer flowers of a flower head in the Asteraceae (aster family).

Rhizome: Belowground modified stem that gives rise to new plants.

Sepal: The outermost part of a flower; typically green and leaflike.

Spikelet: The individual flower clusters of grasses and sedges, consisting of one to many flowers subtended by two bracts (glumes).

Stipules: A pair of leaflike structures found at the base of a leaf.

Stolon: Aboveground modified stem that gives rise to new plants.

Terminal: The tip or end of a stem or leaf.

Thorn: A stiff, woody, modified stem with a sharp point.

Trifoliolate: The word used to describe a compound leaf consisting of three leaflets.

Tuber: The thickened portion of a rhizome bearing nodes and buds; underground stem modified for food storage.

Whorl: Arrangement of three or more parts arising from a common point, as in a leaf arrangement with three or more leaves per node.