162. Acroceras Stapf in Prain, Fl. Trop. Africa. 9: 621. 1920.
凤头黍属 feng tou shu shu
Authors: Shou-liang Chen & Sylvia M. Phillips
Neohusnotia A. Camus.
Annuals or perennials. Culms decumbent, often rooting near the base. Leaf blades flat, lanceolate or linear-lanceolate, usually with obscure transverse veins; ligule a narrow membrane. Inflorescence of lax racemes along a central axis, sometimes panicle-like due to irregular secondary branching; spikelets paired or rarely single, pedicels of each pair connate at base. Spikelets lanceolate to oblong, plump, dorsally or weakly laterally compressed, glabrous, florets 2; glumes subequal or lower glume shorter, papery; upper glume and lower lemma thickened and laterally compressed at apex to form a green crest; upper lemma dorsally compressed, crustaceous, smooth or finely striate, apex glabrous with a little green crest; upper palea with reflexed apex slightly protruding from lemma. x = 9.
Nineteen species: throughout the tropics (12 species endemic to Madagascar); two species in China.
Acroceras species are grasses of damp, shady situations, recognized by the thickened, green crests at the tips of the spikelet scales. The leaf anatomy contrasts with that of the closely related genus Setiacis, with long cells differing in shape on the abaxial and adaxial surfaces, silica bodies short and dumbell-shaped to cross-shaped, and stomatal subsidiary cells dome-shaped.