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.

Arthraxon raizadae

HABIT Annual. Culms geniculately ascending, or decumbent; 10–50 cm long; rooting from lower nodes. Lateral branches sparse. Leaf-sheaths 1–2 cm long; striately veined; glabrous on surface, or pilose; outer margin hairy. Ligule a ciliolate membrane; 1.5 mm long. Leaf-blade base cordate. Leaf-blades lanceolate, or ovate; 2–7 cm long; 4–20 mm wide. Leaf-blade surface pilose; sparsely hairy; with tubercle-based hairs. Leaf-blade margins tuberculate-ciliate. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence composed of racemes. Peduncle 6–12 cm long.

Racemes 1–2; single, or paired; 2–5 cm long. Rhachis fragile at the nodes; ciliate on margins. Rhachis internodes linear; 3.5–4.5 mm long. Rhachis internode tip not enlarged.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels filiform; 2.5 mm long; ciliate; hairy all along but hairs longer above.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; lanceolate; dorsally compressed; 5 mm long; shorter than fertile. Companion sterile spikelet glumes chartaceous; 4–5 mm long; keeled; 6–7 -veined. Companion sterile spikelet lemmas 2; enclosed by glumes; 3.5–4 mm long.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 6–7 mm long; 1–1.3 mm wide; falling entire; deciduous with accessory branch structures. Spikelet callus square; 0.5 mm long; 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. Lower glume primary vein scabrous. Lower glume surface pubescent. Lower glume margins ciliate. Upper glume lanceolate; chartaceous; 1-keeled; keeled above. Upper glume primary vein ciliolate. Upper glume surface pilose; hairy at apex.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; 3–4 mm long; hyaline; obtuse. Fertile lemma lanceolate; 5 mm long; hyaline; without keel. Lemma apex acute; awned; 1 -awned. Principal lemma awn dorsal; arising 0.1 way up back of lemma; geniculate; 15–17.5 mm long overall; with twisted column. Palea absent or minute.

FLOWER Anthers 3; 2–3 mm long.

FRUIT Caryopsis with adherent pericarp; linear; isodiametric; dark brown.

DISTRIBUTION Asia-tropical: India.

NOTES Andropogoneae. Jain 1999.

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