Sorghum bicolor

HABIT Annual. Culms erect; robust; 100–600 cm long; 50–300 mm diam. Culm-nodes glabrous. Leaves cauline. Ligule an eciliate membrane; 1–3 mm long. Leaf-blade base broadly rounded. Leaf-blades 30–100 cm long; 5–10 mm wide.

INFLORESCENCE Inflorescence a panicle with branches tipped by a raceme. Peduncle straight, or deflexed.

Panicle open, or contracted; lanceolate, or ovate, or globose; equilateral, or nodding; 4–50 cm long; 2–20 cm wide. Primary panicle branches appressed, or spreading; not whorled; moderately divided. Panicle branches pubescent, or villous.

Racemes bearing few fertile spikelets; 1–6 fertile spikelets on each. Rhachis tough; ciliate on margins. Rhachis internodes filiform, or linear; 0.5–5 mm long. Rhachis internode tip transverse.

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

STERILE SPIKELETS Companion sterile spikelets well-developed; male; lanceolate; as long as fertile; separately deciduous. Companion sterile spikelet glumes herbaceous; muticous. Companion sterile spikelet lemmas enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong, or ovate, or obovate, or orbicular; dorsally compressed; 3–10 mm long; persistent on plant. Spikelet callus glabrous, or pilose; base obtuse.

GLUMES Glumes dissimilar; with lower wider than upper; exceeding apex of florets; firmer than fertile lemma; parallel to lemmas, or gaping. Lower glume ovate; 1 length of spikelet; chartaceous, or coriaceous; pallid, or red, or black; 2-keeled; keeled above. Lower glume surface glabrous, or pilose. Lower glume apex obtuse, or acute. Upper glume ovate; chartaceous, or coriaceous; 1-keeled; keeled above; 5–7 -veined. Upper glume surface glabrous, or pubescent. Upper glume margins ciliate. Upper glume apex entire, or dentate; 2 -fid.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret elliptic; 0.8 length of spikelet; hyaline; 2–5 -veined; ciliolate on margins. Fertile lemma obovate; 1–3 mm long; hyaline; 1–3 -veined. Lemma margins ciliate. Lemma apex entire, or dentate; 2 -fid; muticous, or awned; 1 -awned. Principal lemma awn from a sinus; geniculate; with twisted column. Column of lemma awn pubescent; hairy on the spiral. Palea present.

FLOWER Lodicules 2; ciliate.

FRUIT Caryopsis exposed between gaping lemma and palea at maturity.

DISTRIBUTION Europe: central, southwestern, southeastern, and eastern. Africa: north, Macaronesia, west tropical, west-central tropical, northeast tropical, east tropical, southern tropical, south, and western Indian ocean. Asia-temperate: Siberia, Soviet far east, Soviet Middle Asia, Caucasus, western Asia, Arabia, China, Mongolia, and eastern Asia. Asia-tropical: India, Indo-China, Malesia, and Papuasia. Australasia: Australia and New Zealand. Pacific: southwestern, south-central, northwestern, and north-central. North America: northwest USA, north-central USA, northeast USA, southwest USA, south-central USA, southeast USA, and Mexico. South America: Mesoamericana, Caribbean, northern South America, western South America, Brazil, and southern South America.

NOTES Andropogoneae. WDC.

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