Sorghum miliaceum var. parvispiculum Snowden
Rhizomatous perennial; culms simple or branched, 0.5-3 m high or more, slender to rather stout. Leaf-blades 20-90 cm long, 0.5-4 cm wide. Panicle loose when in flower, sometimes somewhat contracted after flowering, lanceolate to pyramidal, mostly 10-55 cm long, 3-25 cm wide; primary branches compound, bare at the base, ultimately bearing racemes of 1-5 spikelet pairs. Sessile spikelet elliptic to subelliptic, 45-5(-5.5) mm long, at first ± hairy and cream to buff-yellow or twany, at the length often tawny, mahogany red, purplish to blackish brown or black and sometimes almost glabrous; lower glume keeled above, the wings of the keels widening upwards to end in minute teeth, forming with the short apex a distinctly 3-toothed tip; upper lemma acute and minutely mucronate or 2-lobed with an awn 10-16 mm long. Pedicelled spikelet at length deciduous, often purplish, male, 4.5-6.5 mm long. 2n=40.
Fl. & Fr. Per.: May-October.
Type locality: Syria and Mauritania.
Distribution: Pakistan (Sind, Baluchistan, Punjab, N.W.F.P., Gilgit & Kashmir); Mediterranean region eastwards to Kashmir and southwards to Madras.
Snowden (in J. Linn. Soc., Bot. 55:199. 1955) considers that Sorghum halepense reaches the eastern limit of its range in Kashmir and that it is not native in India. It is widely grown in temperate regions, especially North America, as Johnson Grass, and has been introduced into most warm countries.
Because of its tenacious rhizomatous habit Sorghum halepense has earned a bad reputation as a weed of cultivated fields. Worse than this, under certain circumstances its tissues contain hydrocyanic acid and are a positive danger to stock.
Endrezzi (in Bot Gaz. 119: 1. 1957) considers that Sorghum halepense arose as a segmental allotetraploid from a cross involving Sorghum propinquum (2n=20) and a member of Subsect. Arundinacea (2n=20). Sorghum propinquum extends from China to the Malay Peninsula, but does not occur in India, and is the only diploid Halepensia.