Ischaemum setaceum

HABIT Perennial. Culms prostrate; slender; 15–25 cm long; 2–6 mm diam.; rooting from lower nodes. Culm-internodes distally glabrous. Leaves mostly basal. Leaf-sheaths loose; glabrous on surface. Ligule an eciliate membrane; 1 mm long; truncate. Leaf-blades linear, or lanceolate; 3–5 cm long; 3–4 mm wide. Leaf-blade surface glabrous. Leaf-blade apex acute, or acuminate.

INFLORESCENCE Inflorescence composed of racemes.

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

STERILE SPIKELETS Companion sterile spikelets well-developed; male; ovate; 4 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; keeled; muticous. Companion sterile spikelet lemmas 2; enclosed by glumes; 1-awned; with 10–12 mm long awn.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets linear, or lanceolate; dorsally compressed; 4 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus glabrous; base truncate; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume ovate; 1 length of spikelet; coriaceous; much thinner above; 2-keeled; keeled above; keeled laterally; winged on keel; winged broadly; winged above; 2–8 -veined. Lower glume primary vein scabrous. Lower glume surface flat. Lower glume apex dentate; 2 -fid. Upper glume lanceolate; 1 length of spikelet; coriaceous; 1-keeled; keeled above. Upper glume primary vein ciliate. Upper glume margins ciliate. Upper glume apex emarginate, or obtuse; muticous, or awned. Upper glume awn 1–2 mm long.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret oblong; membranous; ciliate on margins; obtuse. Fertile lemma oblong; 2.5 mm long; hyaline; without keel. Lemma margins ciliate. Lemma apex lobed; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 10–12 mm long overall; with twisted column. Palea 1 length of lemma.

FLOWER Anthers 3.

DISTRIBUTION Asia-temperate: eastern Asia. Pacific: northwestern.

NOTES Andropogoneae. Gr Japan 1996.

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