Sorghum virgatum

HABIT Annual. Culms erect; 50–100 cm long. Culm-nodes glabrous, or pubescent. Leaves cauline. Ligule a ciliolate membrane; 2 mm long. Leaf-blades 15–45 cm long; 4–8 mm wide.

INFLORESCENCE Inflorescence a panicle with branches tipped by a raceme.

Panicle open; lanceolate; 15–60 cm long.

Racemes 1–4 cm long; bearing 3–7 fertile spikelets on each. Rhachis fragile at the nodes; ciliate on margins. Rhachis internodes filiform. Rhachis internode tip transverse; cupuliform.

Spikelets appressed; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels filiform; flattened; ciliate.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; linear to lanceolate; dorsally compressed; 6–7 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; acute; muticous. Companion sterile spikelet lemmas enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; acute; 6.5–7 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus base obtuse.

GLUMES Glumes dissimilar; with lower wider than upper; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 length of spikelet; coriaceous; much thinner above; without keels; keel-less except near apex. Lower glume surface glabrous to pubescent. Lower glume margins ciliolate. Lower glume apex acute. Upper glume lanceolate; coriaceous; much thinner above; without keels. Upper glume surface glabrous to pubescent. Upper glume apex acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; 0.8 length of spikelet; hyaline; 2 -veined; acute. Fertile lemma lanceolate; dorsally compressed; 1–3 mm long; hyaline; 1 -veined. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 8–16 mm long overall; with twisted column. Column of lemma awn glabrous. Palea absent or minute.

FLOWER Lodicules 2; oblong; fleshy. Anthers 3. Stigmas 2.

FRUIT Caryopsis with adherent pericarp. Hilum punctiform. Endosperm farinose. Disseminule comprising a rhachis internode.

DISTRIBUTION Africa: north, west tropical, and northeast tropical. Asia-temperate: western Asia and Arabia.

NOTES Andropogoneae. TAC 1997.

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