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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 castratus
HABIT Perennial. Culms rambling; 60–200 cm long. Culm-nodes glabrous. Leaf-sheaths hirsute; with tubercle-based hairs; outer margin hairy. Ligule a ciliolate membrane; 1.7–2.2 mm long. Leaf-blades lanceolate; 4–11 cm long; 7–15 mm wide. Leaf-blade surface glabrous, or pubescent. Leaf-blade margins ciliate.
INFLORESCENCE Inflorescence composed of racemes. Peduncle pubescent above.
Racemes 1–5; single, or paired, or digitate; flexuous; 2–4 cm long. Rhachis fragile at the nodes; ciliate on margins. Rhachis hairs 0.4–1.5 mm long. Rhachis internodes linear; 4–5.8 mm long.
Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; 2–3 mm long; ciliate.
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; laterally compressed; 6–8 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus pubescent; base obtuse; attached transversely. Spikelet callus hairs 0.4–1.5 mm long.
GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 length of spikelet; chartaceous; without keels; 7 -veined. Lower glume surface convex; scabrous; rough on veins. Lower glume apex acute. Upper glume lanceolate; chartaceous; 1-keeled; keeled above. Upper glume primary vein scabrous. Upper glume apex acute.
FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; 5.2–6.3 mm long; hyaline; ciliate on margins. Fertile lemma lanceolate; 4.4–5.3 mm long; hyaline; without keel; 1 -veined. Lemma apex lobed; 2 -fid; awned; 1 -awned. Principal lemma awn dorsal; arising 0.2 way up back of lemma; geniculate; 10–14 mm long overall; with twisted column. Column of lemma awn 6–8 mm long; glabrous. Palea present; 2.3–2.8 mm long. Palea surface pubescent; hairy on flanks.
FLOWER Anthers 3; 2.4–3.7 mm long.
FRUIT Caryopsis with adherent pericarp; ellipsoid; 3.3 mm long.
DISTRIBUTION Asia-temperate: China. Asia-tropical: India, Indo-China, and Malesia. Australasia: Australia.
NOTES Andropogoneae. Fl Ceyl 1993.
Please cite this publication as detailed in How to Cite Version: 3rd February 2016.
