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 purpureosericeum

HABIT Annual. Culms erect; 30–150 cm long. Culm-nodes bearded. Leaves cauline. Ligule a ciliolate membrane; pilose on abaxial surface. Leaf-blades 10–50 cm long; 2–10 mm wide.

INFLORESCENCE Inflorescence a panicle with branches tipped by a raceme.

Panicle open; oblong; 5–35 cm long. Primary panicle branches whorled at most nodes; simple.

Racemes bearing 3–5 fertile spikelets on each. Rhachis fragile at the nodes; ciliate on margins. Rhachis hairs white, or red; 2–3 mm long. Rhachis internodes filiform; 5 mm long. Rhachis internode tip transverse; cupuliform.

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; linear to lanceolate; 6–10 mm long; shorter than fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; 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; 7.5–10 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus bearded; base obtuse. Spikelet callus hairs white, or red.

GLUMES Glumes dissimilar; with lower wider than upper; exceeding apex of florets; firmer than fertile lemma; shiny. Lower glume ovate; 1 length of spikelet; coriaceous; dark brown, or black; without keels; keel-less except near apex. Lower glume surface glabrous. Lower glume apex acute. Upper glume ovate; coriaceous; without keels. Upper glume surface glabrous.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret elliptic; 0.8 length of spikelet; hyaline; 2 -veined; ciliolate on margins. Fertile lemma oblong; 3–6 mm long; hyaline; 1 -veined. Lemma margins ciliate. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 20–40 mm long overall; with twisted column. Column of lemma awn pubescent; hairy on the spiral. Palea absent or minute.

FLOWER Lodicules 2; ciliate.

DISTRIBUTION Africa: west tropical, west-central tropical, northeast tropical, and east tropical. Asia-temperate: Arabia. Asia-tropical: India.

NOTES Andropogoneae. FTEA.

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