Aristida mutabilis Trin. & Rupr.

Aristida meccana Trin. & Rupr. is very similar to, and perhaps conspecific with Aristida mutabilis. It differs mainly in the relative lengths of the glumes, the upper glume being more than 2.2 mm longer than the lower in Aristida meccana compared with less than 2.2 mm in Aristida mutabilis. However, there is a great deal of overlap although in Africa there is some geographical segregation of populations showing these two ranges. Aristida meccana is marginally the more northerly of the two but with a strong tropical East African element. It occurs throughout much of Arabia and North Africa and there is a single record from Jodhpur in India. That it may yet be found in Pakistan is clear, but it is doubtful if it can really be distinguished from Aristida mutabilis. It would be better, perhaps, to regard Aristida meccana as a variety, or at most a subspecies of Aristida mutabilis, although Bourreil (l.c.) is quite certain that the two should be regarded as distinct species.

Loosely tufted annual; culms (10)30-70 cm high. Leaf-blades linear, 6-14 cm long, narrow or convolute. Panicle narrowly ovate, 12-20 cm long, loose or ± contracted, the spikelets in narrow spikes at the tips of the main branches. Spikelets grey or pallid; glumes typically subequal, lanceolate, scaberulous on the keel and sometimes also on the flanks, the lower 4-5 mm long, the upper 6-7 mm long, acute or apiculate, less often with a short awn-point; lemma terete, 4-5 mm long, scabrid upwards; callus linear, 1-1.5 mm long, finely obtuse at the tip; column 2-5 mm tong, articulated just below the branching point of the awn; awn-branches 10-30 mm long, slender. parallel or divergent.

Distribution: Pakistan (Sind, Baluchistan, Punjab N.W.F.P. & Kashmir); Mauritania to India; perhaps also in tropical East Africa.