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.

Ischaemum raui

HABIT Annual; caespitose. Culms decumbent; 10–30 cm long. Lateral branches ample. Leaf-sheaths 1–4 cm long; mostly shorter than adjacent culm internode; keeled; striately veined; glabrous on surface. Ligule an eciliate membrane; 0.5–1 mm long. Leaf-blades lanceolate, or ovate; 1–3 cm long; 4–6 mm wide. Leaf-blade surface glabrous. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 1, or 2; single, or paired; 1–3 cm long. Rhachis fragile at the nodes; angular; villous on margins. Rhachis internodes clavate; 2.5–3 mm long. Rhachis internode tip transverse; cupuliform.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels oblong; 0.5–1 mm long; villous.

STERILE SPIKELETS Companion sterile spikelets well-developed; bisexual; lanceolate; laterally compressed; 3.5–4 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; keeled; wingless; villous. Companion sterile spikelet lemmas 2; enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; 3.5–4 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus bearded; base truncate; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume ovate; 1 length of spikelet; coriaceous; much thinner above; 2-keeled; keeled all along; keeled laterally; 9–11 -veined. Lower glume lateral veins obscure. Lower glume surface flat; villous; inner surface scabrous. Lower glume apex acute. Upper glume ovate; coriaceous; 1-keeled; keeled above; winged on keel; winged near apex. Upper glume surface villous. Upper glume margins ciliate.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret lanceolate, or ovate; 3.5–4 mm long; membranous; 3–5 -veined; obscurely veined; ciliate on margins; fringed above. Palea of lower sterile floret 3.5–4 mm long. Fertile lemma oblong; 3–3.5 mm long; membranous; without keel; 3 -veined. Lemma lateral veins obscure. Lemma margins ciliolate; hairy above. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 10–12 mm long overall; with twisted column. Column of lemma awn 6–7 mm long; glabrous. Palea 3–3.5 mm long.

FLOWER Lodicules 2; 0.6 mm long. Anthers 3; 1.5–2 mm long.

DISTRIBUTION Asia-tropical: India.

NOTES Andropogoneae. Fl Kerala 2006.

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