Description: Tall annuals or perennials.
Ligule membranous or a ciliate rim, often with hairs at the orifice; blade rolled in bud, flat.
Inflorescence of jointed racemes arranged in an open or dense panicle with secondary branching, rachis disarticulating readily, except in crop varieties.
Spikelets paired, 1 sessile and fertile, the other pedicellate and sterile, terminal spikelets in triplets, falling in groups with an axis joint. Sessile spikelet dorsally compressed, florets 2, upper bisexual, lower sterile. Glumes equal, leathery, lower rounded on the back, margins involute; upper keeled upwards, margins narrow, translucent, hairy on the upper part. Lemmas translucent, ciliate; the lower 2-nerved or nerveless; upper 2-lobed, awnless or with a geniculate awn from the sinus, faintly nerved; paleas minute or absent. Pedicellate spikelet narrower than the sessile spikelet, sometimes reduced or absent, florets 2, both
Distribution and occurrence: World: c. 50 species, Africa, Australia, America, Asia, Europe, Mediterranean region. Australia: c. 24 species (c. 15 species native, 7 species naturalized), all mainland States.
The taxonomy of the group containing the cultivated sorghums is complex and hybrids have not only been produced by plant breeders but are in natural populations. Grain sorghum is an important cereal being a staple food grain in west Africa and widely used for feeding to livestock in western countries. Varieties have also been developed for forage and the inflorescences of one variety are used to make straw brooms. The leaves of many sorghum species contain cyanogenetic glycosides in young stages of growth and have been responsible for stock poisoning. Spangler (2003) suggests that species in Australia belong in 3 genera, Sarga, Sorghum and Vacoparis whilst Price et al (2005) regard the split as premature. Derivation: from an Italian name for a crop variety of Sorghum.
Text by S. W. L. Jacobs & K. L. McClay: updated Jacobs, S.W.L., Whalley, R.D.B. & Wheeler, D.J.B.
Taxon concept: Fl. of NSW, Vol. 4 (1993); updated Grasses of New South Wales, Fourth Edition (2008).
Taxa not yet included in identification key
| ||Key to the species|| |
|1||Nodes bearded with long hairs (pilose); leaf sheaths hairy||Sorghum leiocladum|
|Nodes glabrous or with fine, short hairs (pubescent); leaf sheaths glabrous or hairy||2|
|2||Perennials with well-developed creeping rhizomes; leaf sheaths usually glabrous; panicle large, more or less open||Sorghum halepense|
|Annuals (or weak perennials); rhizomes only rarely present; leaf sheaths glabrous or hairy; panicle open or dense|
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