GrassBase - The Online World Grass Flora


W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Sorghum bulbosum

HABIT Annual. Culms 130–200 cm long; 2–4 mm diam.; 6 -noded; without nodal roots. Culm-nodes bearded. Ligule an eciliate membrane, or a ciliolate membrane; 1.3–2.3 mm long; scaberulous on abaxial surface, or pubescent on abaxial surface. Leaf-blades 3–5.3 mm wide. Leaf-blade surface glabrous, or pilose; with tubercle-based hairs.

INFLORESCENCE Inflorescence a panicle with branches tipped by a raceme.

Panicle open; loose; 14.5–34 cm long; 3–5 cm wide. Primary panicle branches 1–13 -nate; simple; 2–7 cm long; sterile at lowest node. Panicle axis smooth, or scabrous. Panicle branches smooth, or scabrous; glabrous in axils.

Racemes 2–2.3 cm long; bearing a triad of spikelets; bearing 1 fertile spikelets on each. Rhachis obsolete.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 2 in the cluster. Pedicels filiform; flattened; 5.8–6 mm long; ciliate.

STERILE SPIKELETS Companion sterile spikelets well-developed; containing empty lemmas, or male; lanceolate; dorsally compressed; 8.5–13 mm long; as long as fertile; persistent. Companion sterile spikelet glumes membranous, or cartilaginous; 7–9 -veined; pubescent, or pilose; eciliate on margins, or ciliate on margins; acuminate, or setaceously attenuate; muticous. Companion sterile spikelet lemmas enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets obovate; dorsally compressed; compressed slightly; 10–13 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus cuneate; 3–8 mm long; base pungent.

GLUMES Glumes dissimilar; with lower wider than upper; exceeding apex of florets; firmer than fertile lemma; shiny. Lower glume oblong; 1 length of spikelet; coriaceous; much thinner above; black; without keels; keel-less throughout, or except near apex; 7–8 -veined. Lower glume lateral veins ribbed. Lower glume surface glabrous. Lower glume margins ciliate. Lower glume apex rostrate. Upper glume ovate; coriaceous; much thinner above; black; without keels; 7 -veined. Upper glume margins ciliate. Upper glume apex acuminate, or setaceously attenuate.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; hyaline; 2 -veined; acute. Fertile lemma ovate; hyaline; 1 -veined. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 55–90 mm long overall; with twisted column. Column of lemma awn ciliate. Palea absent or minute.

FLOWER Lodicules 2; oblong; 0.5–0.8 mm long; fleshy; ciliate. Anthers 3; 3–3.3 mm long. Stigmas 2. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp; ellipsoid, or obovoid; 4–5 mm long.

DISTRIBUTION Australasia: Australia.

NOTES Andropogoneae. Lazarides 1993.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.