Echinochloa colona

Annual, with fibrous, rather shallow roots. Culms stout, usually reddish-purple, erect, ascending or decumbent, often branching from the base, often rooting at the lower nodes, 20-60 cm tall, sometimes nodes conspicuously swollen and usually geniculate, compressed, lower internodes often exposed. Sheath 3-7 cm long, compressed, keeled, glabrous, ligule absent;leaf blades light green, sometimes with transverse purple bands, flat, glabrous, elongate, 4-10 cm long, 3-8 mm wide, margins occasionally scabrous, apex acute. Panicle erect or nodding, green or purple-tinged, 5-15 cm long. Racemes numerous, 2-4 cm long, spreading, ascending, sometimes branched, the lower ones up to 1 cm apart, the upper ones crowded.
Spikelets green tinged with purple, crowded, arranged in ca 4 rows, about 3 mm long, rarely with a short point up to 1 mm long. First glume, 1.2-1.5 mm long, 3-nerved, nearly half as long as the spikelet;second glume, 2.5-3 mm long, 7-nerved;the first lemma is similar to the second glume, first palea ovate, ca 2 mm long, glabrous;second lemma, broadly ovate, ca 2 mm long, glossy. Caryopsis whitish, broadly ovate, 1.7- 2 mm long, flat on one side, convex on the other (Wagner et al., 1999).
E. colona is smaller, branches more at the base and has a more spreading or open type of growth than E. crus-galli (Williams, 1956a).
Seedlings have rolled leaves with pointed tips. The blades and sheaths are usually, but not always, green. There are no auricles or ligules and stems are circular in cross-section. The lowermost leaf sheath has a few hairs but most other leaf sheaths are smooth. The usually flaccid leaf blade has faint striations, a white midrib and smooth margins, at least in the upper part. Young plants have erect leaves thickened at the base and culms are sometimes flat and spreading (Zimdahl et al., 1989).
The absence of a ligule, the purplish-tinged leaves and the neatly 4-rowed racemes are characteristic of E. colona.