Flora of New Zealand Series

forage sorghum, grain sorghum

Annual robust tufted plants to 1.5 m. Leaf-sheath chartaceous, somewhat keeled near collar, glabrous, or occasionally with sparse, long, fine hairs, straw-coloured, often suffused or blotched reddish purple. Ligule 2-3 mm, stiffly membranous, ciliate. Leaf-blade 30-90 × (1)-2.5-7 cm, with strong pale creamy midrib, linear-lanceolate, long-tapered, glabrous or rarely with a few sparse hairs, adaxially densely pubescent above ligule; margins and filiform tip finely scabrid. Culm internodes often blotched purplish red, pubescent below panicle. Panicle contracted or open, 18-25 × 4-7-(13) cm, branches stiffly ascending or spreading and sometimes pendulous, usually naked below; rachis stout. Racemes several along each branch. Pedicelled spikelet: glumes linear-lanceolate, subcoriaceous; florets Ø, or upper floret ♂; stamens 3, anthers 2.5 mm. Sessile spikelet: glumes 4-6 mm, elliptic-lanceolate to obovate, glabrous to densely pubescent; lemmas hyaline, pubescent, « glumes, lemma of upper floret often awned; stamens 3, anthers 3 mm; caryopsis c. 2.5 × 1.5 mm.

N.: North and South Auckland, Gisborne, Taranaki (Hawera); S.: Marlborough (Seddon). Cultivated ground, crops (often asparagus or maize), roadsides, railway lines.

Naturalised from Africa.

Sorghum bicolor may form hybrids with S. halepense. Hybrid plants are ± rhizomatous and may be difficult to distinguish from Johnson grass.