Enum. Pl. 1: 491 (1833).- Type: Gay s.n., Senegal (iso- K).
Andropogon guineensis Schumach., Beskr. Guin. Pl 51 (1827).
Regional litterature: FI. Agr. Congo Belge 1: 140 (1929); FWTA: 488 (1972); Ghana grasses: 93 (1977); FTEA: 777 (1982); Gram. Togo: 139 (1983); Fl. Mauritania: 438 (1991); Gram. Cameroun: 433 (1992); Poac. CI: 576, fig. (1995); Pl. Mauritanie: 308 (1998); Poaceae Niger : 583, fig. (1999); Fl. Bénin: 180, fig. (2006); Fl. Guinée: 449 (2009); Pl. Burkina Faso: 68 (2012); Fl. Chad (2013); Pl. Sudan & S Sudan: 118 (2015).
Description:
* Tall course erect perennial bunchgrass of 1.0-3.0 m high. Leaves variable, 30-60 cm long and 4-20 mm wide, with or without a false-petiole of up to 10 cm long; sheaths with a purple spot or nectary on each side at the top near the ligule; ligule a glabrous or pubescent membrane.
* Inflorescence compound and lax with numerous flowering branches from the upper culms bearing spathate panicles of pale terminal and axillary paired racemes, subtended by a spatheole. Spatheole lanceolate, 6-8 cm long; herbaceous. Racemes 4-9 cm long; rhachis fragile, glabrous on surface, ciliate on margins; internodes and pedicels cuneate, 4-5 mm long, ciliate.
* Sessile spikelets oblong; dorsally compressed, 5-8 mm long; callus oblong, obtuse, 1 mm long, pilose. Lower glume oblong, coriaceous, keeled laterally, flat, with a longitudinal median groove, glabrous or with very short hairs; upper glume lanceolate, chartaceous, muticous or mucronate. Lower lemma lanceolate, hyaline; upper lemma oblong, hyaline with from the sinus the geniculate awn of 15-40 mm long with twisted column. Pedicelled spikelets elliptic, dorsally compressed, 5-8 mm long; glumes glabrous or villous, acute, one or both glume awned with 1-10 mm long awn.
Note Sales in Cope (2002) considers the varieties as synonyms because, in southern Africa, the internodes and pedicels are with hairs on both sides and half of the material has the pedicelled spikelets with spread short hairs. In western Africa the varieties are a bit more distinct but not lways easy to separate. Perhaps they should be considered as ecotypes. At the base of the racemes the pubescence of pedicels and internodes is more scarce. There are quite some intermediates between var. polycladus and var. bisquamulatus. The varieties with glabrous pedicelled spikelets (var. gayanus, polycladus) are in the swampy areas, the hairy ones on the fringes and roadsides (var. bisquamulatus) or savannas (var. tridentatus).
Key to the varieties:
1. Internodes and pedicels ciliate on one side (sometimes few at the base of the other side up to 1/4); sessile spikelets 6-8 mm long; awn 15-30 mm long, the pedicelled one 1-10 mm long. 2
1'.Internodes and pedicels ciliate on both sides; sessile spikelets 5-8 mm long; awn 15-40 mm long, the pedicelled one 3-7 mm. 3
2. Pedicelled spikelet glabrous; awn of pedicelled spikelet 1-6 mm. var. gayanus
2'.Pedicelled spikelet villous to pubescent; awn of the pedicelled spikelet 5-10 mm. var. tridentatus
3. Pedicelled spikelets glabrous to more or less hairy. var. polycladus
3'.Pedicelled spikelets villous. var. bisquamulatus