Description

Key Characters:

Growth Form: Annuals or perennials.

Stems: Culms solid, decumbent or sometimes erect, usually geniculate.

Roots:

Leaves: Leaves simple. Alternate. Blades flat or folded, nonauriculate. Margins entire. Veins parallel. Sheaths compressed–keeled, open; ligule a fringe of hairs or membranous. Stipules absent.

Flowers: Flowers in inflorescence a highly modified panicle, the spikelets borne singly or in clusters and partially enveloped by a subtending spiny involucre (bur) of basally connate bristles and/or flattened spines (modified branches), disarticulating as a unit, spines often retrorsely barbed, the burs sessile or subsessile; spikelets turgid or somewhat dorsally compressed, 2–flowered, first floret sterile or staminate, second floret fertile; glumes usually unequal, first glume l–nerved or 3–nerved, second glume larger than first glume, 1–7– nerved; sterile or staminate lemma similar in size and texture to second glume,1–7–nerved, palea subequal to lemma, the fertile lemma usually indurate, smooth, 3–5–nerved, apex acuminate, awnless, rounded on the back, margins revolute and clasping palea; palea of fertile floret similar to lemma in texture. Stamens 3. Ovary superior.

Fruit: Caryopsis dorsally flattened; ellipsoid to ovoid.

Ploidy:

Habitat:

Elevation Range: