Sorghum Moench, Methodus 207. 1794; Sharma & Khosla, Grasses Punj. & Chandigarh 237. 1989; Chen & Phillips, Fl. China @ eFloras.org 22: 600; Fl. Pak. @ eFloras.org p. 292.

Annuals or perennials, with or without rhizomes, culms mostly erect, robust. Leaf blades linear, flat, convolute in bud; ligule membranous, ciliate. Inflorescence a large terminal panicle with elongated central axis, usually lax in wild species, frequently contracted or compacted in cultivated species; primary branches simple or branched, bearing short dense racemes of spikelets, racemes fragile (tough in cultivated species), rachis, internodes and pedicels slender, ciliate. Spikelets borne in pairs, one sessile, the other pedicelled.

SESSILE SPIKELETS: Dorsally compressed, 2-flowered. Glumes equal; lower glume +/- subleathery, broadly convex across the back, becoming 2-keeled and narrowly winged near the tip, usually hairy; upper glume nearly similar to lower glume. Lower Floret: Reduced to empty lemma (lower lemma). Upper floret: Bisexual; Its lemma (upper lemma) hyaline, bidentate, with a glabrous awn from the sinus, sometimes entire and muticous; palea hyaline, often minute. Lodicules 2, ciliate. Caryopsis mostly obovoid, dorsally compressed.

PEDICELLED SPIKELETS: Linear-lanceolate to subulate, much narrower than the sessile spikelet, 2- flowered, lower floret barren, the upper male or neuter or almost suppressed, Glumes membranous, awnless.

17 species

Sorghum bicolor (L.) Moench, Methodus 207. 1794; Fl. China @ eFloras.org 22: 601; Graminae in Fl. Taiwan @ eFloras.org; S. vulgare Pers., Syn. Pl. 1: 101. 1805; S. bicolor var. bicolor (L.) Pers. Syn. Pl. 1: 101. 1805; S. bicolor subsp. bicolor (L.) Marie & Weiller, Fl. Afrique N. 1: 270. 1952.

Annual. Culms erect, solid, robust, up to 3 m tall; nodes glabrous or pubescent. Leaf sheaths glabrous, slightly farinose; leaf blades linear-lanceolate, 40-80 cm x 3-7 cm, pubescent at base; ligule suborbicular, membranous, ciliate. Panicle terminal, +/- 30 cm long, lax or dense, cylindrical, pyramidal or obovate in outline; main axis elongate to very short; primary branches ascending or spreading, lower branches sometimes as long as panicle, stiff or pendulous; racemes tough at maturity, bearing 2-6 spikelet-pairs, pairs dimorphic, each pair with one sessile, fertile and other pedicelled sterile spikelet. Pedicel filiform, ciliate.

SESSILE SPIKELET: Shape variable, broadly ovate-elliptic, obovate to subglobose, 5-6 mm long. Glumes coriaceous, hispid, pale green, purple or brown. Glumes nearly equal; lower glume 5-6 mm long, ovate, broadly convex across the back, coriaceous, 2-keeled, creamy-green to brown or purplish-red at maturity, surface pilose, apex acute, 9-15-nerved, nerves tessellate (polygonal areas formed), nerves prominent towards apex; upper glume coriaceous, 5-9- nerved, nerves tessellate. Spikelet 2-flowered. Lower floret: Reduced to barren lemma, lower lemma membranous, elliptic, hyaline, fringed on margins, 2-keeled, 2-5-nerved, 4-4.5 mm long. Upper floret: Bisexual. Its lemma (upper lemma) obovate, ca. 3 mm long, hyaline, 1-3-nerved, margin ciliate, apex 2-fid, muticous. Palea (upper palea) linear-lanceolate, nearly as long as upper lemma but much narrower, hyaline, margin ciliolate. Lodicules 2, hyaline, small, ca. 1 mm long, ciliate. Stamens 3, anthers ca. 3 mm long. dehiscence by apical pores Stigmas 2. Caryopsis large, often exposed between gaping glumes.

PEDICELLED SPIKELET: Sterile, well-developed, often male, as long as sessile spikelet but narrower, linear-elliptical, persistent or deciduous. Glumes herbaceous, glabrous, lower glume 7-nerved and upper 5-nerved. Spikelets 2-flowered; lower floret reduced to lemma, upper floret male. Lower lemma, upper lemma, palea, lodicules and stamens similar as in sessile spikelet.

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