Ischaemum thomasii

HABIT Perennial. Stolons present. Culms erect; slender; 25–45 cm long. Culm-internodes terete; distally glabrous. Culm-nodes glabrous. Leaf-sheaths loose; 3–5 cm long; glabrous on surface; outer margin hairy. Ligule an eciliate membrane; 2–4 mm long; membranous; bilobed; obtuse. Leaf-blades curved; 2–8.5 cm long; 5–8 mm wide. Leaf-blade surface pubescent; hairy on both sides. Leaf-blade apex acute.

INFLORESCENCE Inflorescence composed of racemes; terminal.

Racemes 2; paired; appressed back to back; 3–6 cm long. Rhachis fragile at the nodes; angular; ciliate on margins. Rhachis internodes columnar; 3.5–5 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; 4–4.5 mm long; ciliate.

STERILE SPIKELETS Companion sterile spikelets well-developed; containing empty lemmas, or male; oblong, or ovate; asymmetrical; 5–6 mm long; shorter than fertile; separately deciduous. Companion sterile spikelet glumes free; chartaceous; winged on keels; pilose; dentate; 2 -fid; muticous. Companion sterile spikelet lemmas 2; enclosed by glumes; 4–5 mm long; muticous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; dorsally compressed; 6–7.5 mm long; 1.5–2 mm wide; falling entire; deciduous with accessory branch structures. Spikelet callus oblong; 1.5 mm long; base truncate; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume oblong; asymmetrical; 6–7.5 mm long; 1 length of spikelet; coriaceous; 2-keeled; keeled above; keeled laterally; winged on keel; winged narrowly; winged near apex. Lower glume surface convex; pilose. Lower glume apex dentate; 2 -fid. Upper glume elliptic; 7–7.5 mm long; coriaceous; 1-keeled; winged on keel; winged above. Upper glume surface scabrous. Upper glume margins ciliate. Upper glume apex acuminate.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret lanceolate; 5.5–6 mm long; 0.9 length of spikelet; membranous; ciliate on margins; fringed above. Palea of lower sterile floret hyaline; 5 mm long; pilose; adorned on flanks. Fertile lemma oblong; 4–5 mm long; membranous; without keel. Lemma margins ciliate; hairy above. Lemma apex lobed; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 14–18 mm long overall; with twisted column. Column of lemma awn glabrous. Palea oblong; 4 mm long.

FLOWER Lodicules 2; cuneate; 1 mm long. Anthers 3; 2 mm long.

DISTRIBUTION Asia-tropical: Indo-China.

NOTES Andropogoneae. Traiperm & Boonkend 2012.

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