GrassBase - The Online World Grass Flora

Descriptions

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

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

Sorghum timorense

HABIT Annual. Culms erect, or geniculately ascending; 30–300 cm long; 7–13 mm diam.; without nodal roots, or with prop roots. Culm-internodes distally pruinose, or glabrous. Culm-nodes constricted, or flush with internodes; pubescent, or bearded. Lateral branches sparse. Leaf-sheaths glabrous on surface, or puberulous. Leaf-sheath oral hairs lacking, or bearded. Ligule an eciliate membrane; 1.3–3.5 mm long. Leaf-blades straight, or curled; 30–60 cm long; 5–10 mm wide. Leaf-blade surface glabrous, or pubescent; with tubercle-based hairs. Leaf-blade apex filiform.

INFLORESCENCE Inflorescence a panicle with branches tipped by a raceme.

Panicle open; dense, or loose; 15–40 cm long. Primary panicle branches simple; 2–11 cm long. Panicle axis smooth. Panicle branches angular, or flat; scabrous; rough distally; villous; hairy at tip; glabrous in axils, or bearded in axils; with prominent pulvini.

Racemes bearing few fertile spikelets; 2–10 fertile spikelets on each. Rhachis fragile at the nodes; ciliate on margins. Rhachis internodes linear; 5–6 mm long. Rhachis internode tip oblique.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels filiform; flattened; 5 mm long; ciliate; with white hairs.

STERILE SPIKELETS Companion sterile spikelets well-developed; containing empty lemmas, or male; lanceolate; dorsally compressed; 7–8 mm long; longer than fertile; separately deciduous. Companion sterile spikelet callus square; 1 mm long. Companion sterile spikelet glumes chartaceous; 7–10 -veined; glabrous, or pilose; ciliate on margins; muticous. Companion sterile spikelet lemmas enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate, or oblong; dorsally compressed; 6–7 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus square; 0.3–1.3 mm long; pilose; base obtuse. Spikelet callus hairs tawny; 2 mm long.

GLUMES Glumes dissimilar; with lower wider than upper; exceeding apex of florets; firmer than fertile lemma; dull, or shiny. Lower glume ovate; 1 length of spikelet; coriaceous; much thinner above; 2-keeled; keeled above; 8–9 -veined. Lower glume surface asperulous; rough above; glabrous to pilose; with simple hairs, or tubercle-based hairs. Lower glume margins eciliate, or ciliate. Lower glume hairs yellow. Lower glume apex muticous, or mucronate. Upper glume ovate; coriaceous; much thinner above; without keels; 5–7 -veined. Upper glume surface asperulous; rough above; glabrous to pilose; with simple hairs, or tubercle-based hairs. Upper glume hairs tawny. Upper glume apex setaceously attenuate.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; hyaline; 2 -veined; acute. Fertile lemma oblong; hyaline; 1 -veined. Lemma apex lobed; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 30–45 mm long overall; with twisted column. Column of lemma awn glabrous. Palea absent or minute.

FLOWER Lodicules 2; oblong; 0.5–0.9 mm long; fleshy; glabrous, or ciliate. Anthers 3; 2.6–5 mm long; yellow, or orange. Stigmas 2.

FRUIT Caryopsis with adherent pericarp; ellipsoid, or obovoid; dorsally compressed; 2.6 mm long.

DISTRIBUTION Asia-tropical: Malesia. Australasia: Australia.

NOTES Andropogoneae. Lazarides 1993.

Please cite this publication as detailed in How to Cite Version: 27th January 2014.