Ischaemum Linn., Sp. Pl. 2:1049. 1753. Gen. Pl., ed. 5, 469. 1754; Hook. f., Fl. Brit. Ind. 7: 126. 1896; Blatter & McCann, Bombay Grasses 10. 1935; Bor, Fl. Assam 5: 421. 1940; Sultan & Stewart, Grasses W. Pak. 1:131. 1958; Bor, Grasses Burma Ceyl. Ind. Pak. 171. 1960.
Perennials, often decumbent, sometimes annuals. Leaf-blades linear; ligule membranous. Inflorescence of paired or digitate racemes, the former often inter-locked back to back, terminal or axillary, internodes and pedicels clavate to inflated. Sessile spikelet dorsally compressed, the callus obtuse and inserted into the concave tip of the internode; lower glume chartaceous to coriaceous, convex to concave, laterally 2-keeled, sometimes winged; upper glume awned or not; lower floret male with a palea; upper lemma bifid, passing between the teeth into a glabrous awn (rarely awnless). Caryopsis oblong to lanceolate, dorsally compressed. Pedicelled spikelet as large as the sessile or much smaller, often asymmetrical.
A genus of about 60 species in the Old World tropics, mainly in Asia, but a few species in tropical America; 2 species occur in Pakistan.
The male lower floret, though awkward to use, provides the best distinction between Ischaemum and Andropogon. A helpful additional character in many species is the U-shaped appearance of the intemode and pedicel seen from the back of the raceme. Ischaemum is a difficult genus reaching its greatest complexity in Southeast Asia where some serious biosystematic work badly needs doing.
Ischaemum timorense Kunth has been reported from Pakistan (see Grasses W. Pak. 1:133) but no herbarium specimens are available for confirmation. In this species the margins of the lower glume of the sessile spikelet are expanded below the middle, not inturned; the glume is perfectly smooth on the back and 2.5-3 mm long.
