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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 longispinus
HABIT Annual; caespitose. Culms geniculately ascending, or decumbent; 10–90 cm long. Leaf-sheaths keeled; outer margin hairy. Leaf-sheath oral hairs ciliate. Ligule a fringe of hairs; 0.7–1.7 mm long. Leaf-blades 6.3–18.7 cm long; 3–7.2 mm wide. Leaf-blade surface glabrous, or pilose; sparsely hairy.
INFLORESCENCE Inflorescence a panicle.
Panicle spiciform; linear; dense (internodes 2–5mm); 4.1–10.2 cm long; 1.2–2.2 cm wide. Primary panicle branches accrescent to a central axis; burrs 6–18 in number; with sessile scars on axis. Panicle axis angular; scaberulous; bearing deciduous spikelet clusters.
Spikelets subtended by an involucre. Fertile spikelets sessile; 2–3 in the cluster. Involucre composed of bristles; connate into a cup below; globose; 8.3–11.9 mm long; base obconical; base pubescent. Involucral bristles deciduous with the fertile spikelets; numerous; emerging irregularly from body of a burr; 46–75 in principal whorl; 3.5–7 mm long; flattened; without grooves, or grooved on the face; rigid; retrorsely scaberulous; pubescent; spinose.
FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; acuminate; 6–7.8 mm long; falling entire; deciduous with accessory branch structures.
GLUMES Glumes shorter than spikelet; thinner than fertile lemma. Lower glume ovate; 1.5–3.8 mm long; 0.25–0.5 length of spikelet; membranous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume ovate; 4.4–6 mm long; 0.75 length of spikelet; membranous; without keels; 3–5 -veined. Upper glume apex acute.
FLORETS Basal sterile florets barren; with palea. Lemma of lower sterile floret ovate; 5–6.5 mm long; 0.8 length of spikelet; membranous; 3–7 -veined; acute. Fertile lemma ovate; 5.8–7.6 mm long; coriaceous; much thinner on margins; without keel; 3 -veined. Lemma margins flat. Lemma apex obtuse. Palea coriaceous.
FLOWER Anthers 0.8–2.1 mm long.
FRUIT Caryopsis with adherent pericarp.
DISTRIBUTION Australasia: Australia. North America: eastern Canada. South America: Caribbean and southern South America.
NOTES Paniceae. De Lisle.
Please cite this publication as detailed in How to Cite Version: 3rd February 2016.
