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 depressus

HABIT Annual. Culms rambling; slender; 30–60 cm long. Culm-nodes glabrous. Leaf-sheaths glabrous on surface; outer margin hairy. Ligule a ciliolate membrane; 2–2.8 mm long. Leaf-blade base broadly rounded. Leaf-blades lanceolate, or ovate; 5–9 cm long; 10–26 mm wide. Leaf-blade surface glabrous. Leaf-blade margins ciliate.

INFLORESCENCE Inflorescence composed of racemes. Peduncle 17 cm long; glabrous, or pubescent above.

Racemes 2–4; digitate; 2–5.6 cm long. Rhachis fragile at the nodes; pubescent on surface. Rhachis internodes filiform; 3.5–4.6 mm long.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels filiform; 2.2–3.5 mm long; pubescent.

STERILE SPIKELETS Companion sterile spikelets represented by barren pedicels.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; subterete; 6.8 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus pubescent; base truncate; attached transversely.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 length of spikelet; coriaceous; 2-keeled; 7 -veined. Lower glume surface scabrous, or spinose; rough above. Upper glume lanceolate; chartaceous; 1-keeled; keeled above; 3 -veined. Upper glume apex acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; 5.6 mm long; hyaline; 0 -veined; without midvein; without lateral veins; ciliolate on margins. Fertile lemma lanceolate; 4.8 mm long; hyaline; without keel; 1 -veined. Lemma apex acute; awned; 1 -awned. Principal lemma awn dorsal; arising 0.2 way up back of lemma; geniculate; 9.5 mm long overall; with twisted column. Column of lemma awn 6 mm long; glabrous. Palea 2.5 mm long.

FLOWER Anthers 3; 3.4 mm long.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION Asia-tropical: India.

NOTES Andropogoneae. Welzen 1993.

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