Digitaria bicornis

HABIT Annual. Culms decumbent; 20–45 cm long; without nodal roots, or rooting from lower nodes. Leaf-sheaths glabrous on surface, or pilose; with tubercle-based hairs. Ligule an eciliate membrane; 2 mm long; truncate. Leaf-blades elliptic; 1–12 cm long; 2–8 mm wide. Leaf-blade surface scaberulous; rough on both sides; pilose; hairy on both sides; with tubercle-based hairs. Leaf-blade margins unthickened, or cartilaginous; undulate; scabrous. Leaf-blade apex acute.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 2–4; paired, or digitate; straight; unilateral; 5–10 cm long. Rhachis narrowly winged; angular; scabrous on margins.

Spikelets in pairs. Fertile spikelets pedicelled; 2 in the cluster; heteromorphic (lower almost glabrous). Pedicels scabrous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; acute; 3 mm long; falling entire.

GLUMES Glumes two. Lower glume ovate; 0.2–0.5 mm long; 0.1 length of spikelet. Lower glume apex obtuse. Upper glume lanceolate; 0.66 length of spikelet; membranous; 3 -veined. Upper glume surface glabrous. Upper glume margins ciliate, or setose. Upper glume apex acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret elliptic; 1 length of spikelet; membranous; 5 -veined; with thickened veins; ribbed; pilose, or setose (upper spikelet); hairy between veins but central interspaces glabrous; ciliate on margins; acute. Fertile lemma elliptic; 3 mm long; cartilaginous; much thinner on margins; light brown; without keel; 3 -veined. Lemma surface smooth. Lemma margins flat; covering most of palea. Lemma apex acute. Palea cartilaginous.

FLOWER Anthers 3; 0.5–1 mm long.

FRUIT Caryopsis with adherent pericarp; ellipsoid; 2–2.5 mm long. Embryo 0.5 length of caryopsis. Hilum punctiform.

DISTRIBUTION Africa: north and western Indian ocean. Asia-temperate: China and eastern Asia. Asia-tropical: India, Indo-China, Malesia, and Papuasia. Australasia: Australia. Pacific: southwestern, northwestern, and north-central. North America: Mexico. South America: Mesoamericana, western South America, Brazil, and southern South America.

NOTES Paniceae. Bor 1993.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.