GrassBase - The Online World Grass Flora


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

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

Cenchrus tribuloides

HABIT Annual. Culms 10–70 cm long. Leaf-sheaths outer margin hairy. Leaf-sheath oral hairs ciliate. Ligule a fringe of hairs; 1–2.1 mm long. Leaf-blades 2–14 cm long; 3–14 mm wide. Leaf-blade surface glabrous. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle.

Panicle spiciform; linear; dense, or loose (internodes 3–10mm); 2–8.2 cm long; 1.5–3 cm wide. Primary panicle branches accrescent to a central axis; with sessile scars on axis. Panicle axis angular; smooth, or 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; 9–16 mm long; base obconical; base glabrous. Involucral bristles deciduous with the fertile spikelets; numerous; emerging irregularly from body of a burr; 15–44 in principal whorl; 4–8 mm long; flattened; rigid; retrorsely scaberulous; ciliate; spinose.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; acuminate; 6–8.8 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes shorter than spikelet; thinner than fertile lemma. Lower glume ovate; 1–4 mm long; 0.2–0.5 length of spikelet; membranous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume ovate; 4.9–6.8 mm long; 0.75 length of spikelet; membranous; without keels; 3–7 -veined. Upper glume apex acute.

FLORETS Basal sterile florets barren; with palea. Lemma of lower sterile floret ovate; 5.5–7.5 mm long; 0.8–0.9 length of spikelet; membranous; 3–7 -veined; acute. Fertile lemma ovate; 6–8.7 mm long; coriaceous; much thinner on margins; without keel; 3 -veined. Lemma margins flat. Lemma apex obtuse. Palea coriaceous.

FLOWER Anthers 0.8–2.8 mm long.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION Pacific: southwestern and north-central. North America: northeast USA and southeast USA. South America: Caribbean and Brazil.

NOTES Paniceae. De Lisle.

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