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.

Urelytrum annuum

HABIT Annual; caespitose. Culms erect; 90–120 cm long; 3–5 -noded. Leaf-sheaths glabrous on surface. Leaf-sheath auricles erect. Ligule an eciliate membrane; 3 mm long. Leaf-blades flat, or convolute; 15–30 cm long; 2–3 mm wide. Leaf-blade surface scabrous; rough on both sides. Leaf-blade margins scabrous. Leaf-blade apex attenuate; filiform.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 1; single; 10–15 cm long. Rhachis fragile at the nodes; semiterete; glabrous on surface, or pubescent on surface. Rhachis internodes linear; 4–5 mm long. Rhachis internode tip oblique; crateriform; with scarious rim.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; glabrous, or pubescent; tip cupuliform.

STERILE SPIKELETS Companion sterile spikelets rudimentary, or well-developed; containing empty lemmas, or male; elliptic; 1–7 mm long; shorter than fertile; persistent. Companion sterile spikelet glumes coriaceous; awned; one glume awned; with 25–35 mm long awn.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; dorsally compressed; 5–7 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus oblong; pubescent; base obtuse; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume elliptic; 1 length of spikelet; coriaceous; without keels; keel-less except near apex. Lower glume surface smooth. Lower glume apex acute. Upper glume ovate; chartaceous; 1-keeled; 3 -veined. Upper glume primary vein ciliolate.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret lanceolate; hyaline; 2 -veined; ciliolate on margins. Fertile lemma lanceolate; hyaline; without keel; 3 -veined. Lemma margins ciliolate. Lemma apex acute. Palea hyaline.

DISTRIBUTION Africa: west tropical.

NOTES Andropogoneae. FTA.

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