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.

Arthraxon cuspidatus

HABIT Annual. Culms erect, or geniculately ascending; 40–45 cm long. Culm-nodes bearded. Lateral branches lacking, or sparse. Leaf-sheaths hirsute; with tubercle-based hairs. Ligule a ciliate membrane. Leaf-blade base cordate. Leaf-blades lanceolate; 3–7 cm long; 8–12 mm wide; flaccid. Leaf-blade surface pilose; sparsely hairy; hairy on both sides; with tubercle-based hairs. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 4–5; digitate; 3–5 cm long. Rhachis fragile at the nodes; ciliate on margins. Rhachis hairs lengthening towards internode tip; 2–3 mm long. Rhachis internodes linear; 3 mm long.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels filiform; 3 mm long; villous; with 2–3 mm long hairs.

STERILE SPIKELETS Companion sterile spikelets represented by single glumes; linear, or lanceolate; 4 mm long; shorter than fertile. Companion sterile spikelet glumes 3 -veined.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 5–7 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus bearded; base truncate; attached transversely.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 length of spikelet; chartaceous; without keels; 9 -veined. Lower glume surface convex; muricate; rough on veins. Lower glume apex attenuate. Upper glume lanceolate; membranous; 1-keeled; keeled above; 3 -veined. Upper glume margins ciliolate. Upper glume apex setaceously attenuate.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; 3–4 mm long; hyaline; 0 -veined; without midvein; without lateral veins; obtuse. Fertile lemma linear; hyaline; without keel; 2 -veined. Lemma apex acute; awned; 1 -awned. Principal lemma awn dorsal; arising 0.2 way up back of lemma; geniculate; 16 mm long overall; with twisted column. Column of lemma awn glabrous. Palea absent or minute.

FLOWER Anthers 2; 0.5 mm long.

DISTRIBUTION Africa: northeast tropical. Asia-temperate: Arabia. Asia-tropical: India.

NOTES Andropogoneae. FTA 1993.

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