Sorghum bicolor (Linn.) Moench

Meth. Pl.: 207 (1794).- Type: Herb. Clifford 468 (lecto- BM); Herb. Linn. 1212-? (holo- LINN).

Holcus bicolor Linn., Mant. Pl. Alt.: 301 (1771);

Sorghum vulgare Pers., Syn. Pl. 1: 101 (1805) nom. illeg.;

Sorghum ankolib (Hack.) Stapf, FTA 9:  (1917).- Type: Schweinfurth 1530, Sudan, Gallabat (iso- K);

Sorghum caudatum  (Hack.) Stapf, FTA 9: 131 (1917).- Type: Sudan.

Regional litterature: FWTA: 464, fig. 448 (1972); Ghana grasses: 238 (1977); Gram. Cameroun: 405 (1992); Fl. Bénin: 245, fig. (1992); Poac. CI : 478, fig. (1995); Fl. Ethiopia & Eritrea 7: 300 (1995); Poac. Niger : 509, fig. (1999); Fl. Guinea Bissau: 143 (2008); Pl. Burkina Faso: 114 (2012); Fl. Chad (2013); Pl. Sudan & S Sudan: 147 (2015)

Description:

* Annual crop plant with robust massif culms, 2- 6 m long and 1-3 cm diameter. Leaves linear, base broadly rounded, 0.3-1 m long and 5-10 cm wide; ligule an eciliate membrane of 1-3 mm long.

* Inflorescence an open or contracted lanceolate to globular panicle, straight or nodding, 4-50 cm long, 2-20 cm wide, with branches tipped by a raceme. Branches appressed or spreading, not whorled, pubescent or villous. Racemes bearing 1-6 pairs of spikelets each, the terminal raceme with a triad of spikelets; rachis tough, ciliate on margins; internodes filiform, 0.5-5 mm long. Pedicels filiform, ciliate.

* Sessile spikelets oblong, orbicular to ovate or ob ovate, 3-10 mm long, persistent on the plant; callus obtuse. Lower glume ovate, chartaceous or coriaceous, pallid, red or black, often with reddish to purplish spots, acute; upper glume ovate, chartaceous or coriaceous, entire or dentate; margins ciliate. Lower lemma elliptic, 3-8 mm long, hyaline; upper lemma ob ovate, 1-3 mm long, hyaline, entire or dentate, muticous or with geniculate awn of up to 1cm from a sinus with twisted pubescent column. Caryopsis exposed between gaping lemma and palea, at maturity 4-8 mm diameter, varying in shape and color. Pedicelled spikelets male, lanceolate. Glumes herbaceous, muticous. Lemmas enclosed by glumes.

Note: Annual with massif culms and sessile spikelets in an open to glabular and contracted panicle. Quite some varieties and cultivars. Scholz, HU, 1983 and FEE 1995 give quite some cultivated varieties and subvarieties

-bicolor relatively small grain enclosed by the glumes; loose panicle with long branches. A primitive type

-guinea discoid grains twisted sideways with respect to the glumes; glumes long and gaping; loose panicle; type preferred in high rainfall areas.

-caudatum grains gibbous on the embryo side; compact panicle. The staple sorghum from Sudan westwards to Nigeria.

-durra, grain flat, obovate, bulging at the top with a narrow wedge-shaped base; glumes transversely creasted; compact panicle. Parts of the Sahel.

Distribution West Africa: Senegal, Gambia, Mali, Burkina Faso, Ghana, Niger, Nigeria, Cameroon, Chad, Sudan, South Sudan.

Distribution world-wide: Introduced worldwide in the tropics.

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