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.

Cenchrus platyacanthus

HABIT Annual. Culms 20–90 cm long. Leaf-sheaths pubescent; outer margin hairy. Leaf-sheath oral hairs ciliate. Ligule a fringe of hairs; 1.4–2.3 mm long. Leaf-blades 4–24 cm long; 2–8 mm wide. Leaf-blade surface glabrous. Leaf-blade apex acute.

INFLORESCENCE Inflorescence a panicle.

Panicle spiciform; linear; dense (internodes 0.6–1.4mm); 3.8–8.6 cm long; 0.6–2 cm wide. Primary panicle branches accrescent to a central axis; with sessile scars on axis. Panicle axis angular; scaberulous; bearing deciduous spikelet clusters.

Spikelets subtended by an involucre. Fertile spikelets sessile; 1 in the cluster. Involucre composed of bristles; connate into a cup below; ovate; 2.8–6 mm long; base obtuse. Involucral bristles deciduous with the fertile spikelets; emerging irregularly from body of a burr; 5–10 in principal whorl; 1.8–3 mm long; terete; rigid; retrorsely scaberulous; glabrous, or pubescent; spinose.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; acuminate; 2.4–5.8 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes shorter than spikelet; thinner than fertile lemma. Lower glume ovate; 0.3–1.1 mm long; 0.1–0.2 length of spikelet; membranous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume ovate; 1.9–3.4 mm long; 0.6–0.8 length of spikelet; membranous; without keels; 3 -veined. Upper glume apex acute.

FLORETS Basal sterile florets barren; with palea. Lemma of lower sterile floret ovate; 2.4–3.7 mm long; 0.6–1 length of spikelet; membranous; 3 -veined; acute. Fertile lemma ovate; 2.2–5.8 mm long; coriaceous; much thinner on margins; without keel; 3 -veined. Lemma margins flat. Lemma apex obtuse. Palea coriaceous.

FLOWER Anthers 0.5–1 mm long.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION South America: western South America.

NOTES Paniceae. De Lisle.

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