Ischaemum barbatum

HABIT Perennial. Culms erect, or geniculately ascending; 60–120 cm long. Ligule an eciliate membrane; 2–3.5 mm long. Leaf-blades 10–20 cm long; 5–10 mm wide.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 2; paired; appressed back to back; 5–7 cm long. Rhachis fragile at the nodes; angular; ciliate on margins. Rhachis internodes columnar; 4.5 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; 1–2 mm long; ciliate.

STERILE SPIKELETS Companion sterile spikelets well-developed; containing empty lemmas, or male; oblong; asymmetrical; 6 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; winged on keels; muticous. Companion sterile spikelet lemmas 2; enclosed by glumes; muticous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; dorsally compressed; 5.5–7 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus square; glabrous, or pubescent; base truncate; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume oblong; asymmetrical; 1 length of spikelet; coriaceous; much thinner above; 2-keeled; keeled above; keeled laterally; winged on keel; winged narrowly; winged above. Lower glume surface convex; muricate; rough on flanks. Lower glume apex acute. Upper glume lanceolate; coriaceous; much thinner above; 1-keeled. Upper glume margins ciliate. Upper glume apex acuminate.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret lanceolate; 4.6 mm long; 0.75 length of spikelet; membranous; 3 -veined. Fertile lemma oblong; membranous; without keel; 3 -veined. Lemma apex lobed; 2 -fid; incised 0.75 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 10–15 mm long overall; with twisted column. Column of lemma awn glabrous. Palea 1 length of lemma.

DISTRIBUTION Africa: west tropical. Asia-temperate: China and eastern Asia. Asia-tropical: India, Indo-China, Malesia, and Papuasia. Australasia: Australia. Pacific: southwestern and northwestern.

NOTES Andropogoneae. Gilliland.

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