Ischaemum heterotrichum

HABIT Perennial. Culms rambling; 60–120 cm long; rooting from lower nodes. Ligule an eciliate membrane; 1–2 mm long. Leaf-blade base broadly rounded. Leaf-blades lanceolate; 5–15 cm long; 9–15 mm wide. Leaf-blade surface glabrous. Leaf-blade margins scabrous.

INFLORESCENCE Inflorescence composed of racemes; subtended by a spatheole; exserted, or embraced at base by subtending leaf. Spatheole lanceolate; 4–5 cm long.

Racemes 2; paired; appressed back to back; 5–6 cm long. Rhachis fragile at the nodes; angular; ciliate on margins. Rhachis internodes columnar; 4 mm long; 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 columnar; 4 mm long; 0.4–0.5 length of fertile spikelet; ciliate.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; lanceolate; 5–7 mm long; shorter than fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; keeled; winged on keels; 7 -veined; glabrous; muticous. Companion sterile spikelet lemmas muticous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; 9 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus oblong; 2 mm long; base truncate; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume elliptic; 1 length of spikelet; coriaceous; much thinner above; 2-keeled; keeled above; keeled laterally; winged on keel; winged narrowly; winged above; 4 -veined. Lower glume surface convex. Lower glume apex dentate; 2 -fid. Upper glume lanceolate; coriaceous; 1-keeled; keeled above; winged on keel. Upper glume margins ciliolate. Upper glume mucronate.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret lanceolate; membranous; 3 -veined; ciliate on margins. Fertile lemma oblong; membranous; without keel. Lemma apex lobed; 2 -fid; incised 0.5 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 12–15 mm long overall; with twisted column. Column of lemma awn glabrous.

FLOWER Anthers 3.

DISTRIBUTION Africa: western Indian ocean. Asia-tropical: Indo-China.

NOTES Andropogoneae. Hack 1994.

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