Annual or perennial herbs or occasionally suffrutices. Leaf-blades terete or linear; ligule a fringe of hairs. Inflorescence an open or contracted panicle. Spikelets all alike, bisexual, 1-flowered, disarticulating above the glumes at maturity, the rhachilla not produced beyond the floret; glumes scarious, usually exceeding the lemma; lemma ± indurated at maturity, terete and clasping the caryopsis, prolonged into a well-developed callus below, 1-3-nerved, the nerves converging upwards and produced into an awn; awn 3-branched (rarely the lateral branches absent), the branches sometimes separated from the lemma by a twisted column, articulated or not; palea much shorter than the lemma; lodicules 2 or 0; stamens 3 or 1; stigmas 2. Grain with large embryo and linear hilum; starch grains compound. Chromosomes small, basic number 11.

Genera 3; tropics and subtropics, often in dry climates or on poor soils; 2 genera and 14 species in Pakistan.

Although obviously allied to Arundineae and Eragrostideae, the tribe stands alone on account of its unusual leaf anatomy. In terms of gross morphology it is easily recognised by the 3-pronged awn.

Lower Taxa

• Aristida Linn.
• Stipagrostis Nees