Sorghum drummondii

HABIT Annual; culms solitary. Culms erect; 150–200 cm long; 3–6 mm diam. Leaves cauline. Ligule a ciliolate membrane. Leaf-blades 15–20 cm long; 8–12 mm wide.

INFLORESCENCE Inflorescence a panicle with branches tipped by a raceme.

Panicle open; ovate, or pyramidal; 15–30 cm long; 8–15 cm wide. Primary panicle branches ascending, or spreading; 2–5 -nate; 5–15 cm long. Panicle branches flexuous; scaberulous.

Racemes 1.5–2.5 cm long; bearing few fertile spikelets; bearing 2–5 fertile spikelets on each. Rhachis tough; ciliate on margins. Rhachis hairs 0.5–0.75 mm long. Rhachis internodes filiform; 2.5–4 mm long. 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; 2–3.5 mm long; ciliate; with 0.5–0.75 mm long hairs.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; lanceolate; dorsally compressed; 5.5–8 mm long; shorter than fertile; persistent. Companion sterile spikelet glumes chartaceous; 9–11 -veined; glabrous; acute; muticous. Companion sterile spikelet lemmas enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; subacute; 6–7.5 mm long; 2–3 mm wide; persistent on plant. Spikelet callus pilose; base obtuse.

GLUMES Glumes dissimilar; with lower wider than upper; exceeding apex of florets; firmer than fertile lemma; shiny. Lower glume elliptic; 1 length of spikelet; coriaceous; much thinner above; yellow, or light brown; without keels; keel-less except near apex; 11–15 -veined. Lower glume primary vein scabrous. Lower glume lateral veins with cross-veins. Lower glume surface glabrous, or puberulous. Lower glume apex acute. Upper glume elliptic; coriaceous; much thinner above; without keels; keel-less except near apex; 7 -veined. Upper glume primary vein scabrous. Upper glume lateral veins with cross-veins. Upper glume apex acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret elliptic; 5–6.5 mm long; hyaline; 2 -veined; ciliate on margins; acute. Fertile lemma ovate; 3.5–4.5 mm long; hyaline; 1 -veined. Lemma margins ciliate. Lemma apex dentate; 2 -fid; with lobes 0.5–1 mm long; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 10–16 mm long overall; with twisted column. Column of lemma awn glabrous. Palea absent or minute.

FLOWER Lodicules 2; oblong; fleshy; ciliate; hairy across the apex. Anthers 3; 4 mm long. Stigmas 2; laterally exserted.

FRUIT Caryopsis with adherent pericarp; ellipsoid, or obovoid; dorsally compressed; 3.5–4.5 mm long. Hilum punctiform. Endosperm farinose.

DISTRIBUTION Europe: central, 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 Middle Asia, Caucasus, western Asia, Arabia, China, and Mongolia. Asia-tropical: India and Malesia. Australasia: Australia. Pacific: southwestern, south-central, northwestern, and north-central. North America: north-central USA, southwest USA, southeast USA, and Mexico. South America: Mesoamericana, Brazil, and southern South America.

NOTES Andropogoneae. =Sorghum sudanense. Snowden 1994.

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