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.

Ischaemum tumidum

HABIT Annual. Culms decumbent; 10–30 cm long. Culm-nodes glabrous, or pubescent. Leaf-sheaths outer margin glabrous, or hairy. Ligule a ciliolate membrane; 1.5 mm long. Leaf-blade base broadly rounded, or cordate. Leaf-blades oblong, or ovate; 2–5 cm long; 7–13 mm wide. Leaf-blade margins scabrous. Leaf-blade apex acute, or acuminate.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 2; paired; 2–3 cm long. Rhachis fragile at the nodes; semiterete; glabrous on surface, or pubescent on surface. Rhachis internodes inflated; 8.5 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; 1 mm long; 0.15 length of fertile spikelet; villous.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; oblong; laterally compressed; 4 mm long; shorter than fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; keeled. Companion sterile spikelet lemmas 2; enclosed by glumes; entire; muticous.

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 square; 1 mm long; pilose; 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; winged on keel; winged narrowly. Lower glume primary vein ciliolate. Lower glume surface muricate; rough on flanks; glabrous, or pilose. Lower glume hairs white. Lower glume apex acute. Upper glume lanceolate; coriaceous; much thinner above; 1-keeled; 3 -veined. Upper glume surface pilose.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret lanceolate; 4 mm long; hyaline; 3 -veined. Fertile lemma oblong; 4 mm long; hyaline; without keel; 3 -veined. Lemma apex lobed; 2 -fid; incised 0.5 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 14 mm long overall; with twisted column. Column of lemma awn 7 mm long; glabrous. Palea 1 length of lemma.

FLOWER Anthers 3; 2.5–3 mm long.

DISTRIBUTION Asia-tropical: India.

NOTES Andropogoneae. Bor 1993.

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