Ischaemum magnum

HABIT Perennial. Culms 100–200 cm long. Leaf-sheaths pilose; with tubercle-based hairs; outer margin hairy. Leaf-sheath auricles erect. Ligule an eciliate membrane; 4 mm long. Leaf-blade base with a false petiole. Leaf-blades lanceolate; 15–30 cm long; 9–18 mm wide. Leaf-blade margins scabrous. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 2; paired; appressed back to back; 9–15 cm long. Rhachis fragile at the nodes; angular; ciliate on margins. Rhachis internodes oblong; 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 oblong; 0.25 length of internode; ciliate.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; lanceolate; laterally compressed; 6.4 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; keeled; winged on keels (1 keel). Companion sterile spikelet lemmas 2; enclosed by glumes; 1-awned; with 5 mm long awn.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; dorsally compressed; 6.4 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus pilose; base truncate; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; coriaceous; much thinner above; 2-keeled; keeled all along; keeled laterally; wingless. Lower glume surface flat; muricate; rough on flanks. Lower glume margins ciliate. Lower glume apex acute. Upper glume lanceolate; 6 mm long; coriaceous; 1-keeled; 5 -veined. Upper glume primary vein ciliate. Upper glume margins ciliate. Upper glume apex acuminate.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret ovate; 5.2 mm long; membranous; 3 -veined. Fertile lemma oblong; 4.6 mm long; membranous; without keel; 3 -veined. Lemma apex lobed; 2 -fid; incised 0.33 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; curved; 5–10 mm long overall; with twisted column. Column of lemma awn glabrous.

FLOWER Anthers 3; 3 mm long.

DISTRIBUTION Asia-temperate: China. Asia-tropical: Indo-China and Malesia.

NOTES Andropogoneae. Gilliland 1993.

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