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 diplopogon

HABIT Annual. Culms 30–50 cm long. Culm-nodes glabrous. Lateral branches ample. Leaf-sheaths glabrous on surface. Ligule an eciliate membrane. Leaf-blades linear, or lanceolate; 7.5–15 cm long; 6–16 mm wide; dark green. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence composed of racemes; subtended by a spatheole. Spatheole lanceolate; 2.5–7.5 cm long.

Racemes 2; paired; 2.5–4.5 cm long. Rhachis fragile at the nodes; angular; ciliate on margins. Rhachis internodes clavate; 0.5 length of fertile spikelet; flat and forming a U or V shape with the pedicel in rear view. Rhachis internode tip transverse; cupuliform.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels clavate; 0.5 length of fertile spikelet; ciliate.

STERILE SPIKELETS Companion sterile spikelets well-developed; containing empty lemmas, or male; lanceolate; laterally compressed; 6 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; keeled.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; dorsally compressed; 6 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus oblong; 1.25 mm long; base truncate; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; coriaceous; 2-keeled; keeled all along; keeled laterally. Lower glume surface convex; laterally waisted; with marginal tufts of hair (2 tufts). Lower glume apex dentate; 2 -fid. Upper glume lanceolate; coriaceous; 1-keeled; 3 -veined. Upper glume margins ciliate. Upper glume awned; 1 -awned. Upper glume awn 5 mm long.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret oblong; membranous; 1 -veined. Fertile lemma oblong; 4 mm long; membranous; without keel. Lemma apex lobed; 2 -fid; incised 0.5 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 10–16 mm long overall; with twisted column. Column of lemma awn glabrous.

FLOWER Anthers 3.

DISTRIBUTION Asia-tropical: India.

NOTES Andropogoneae. Blatt & McCann 1994.

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