Apocopis siamensis

HABIT Annual. Culms slender; 20–45 cm long. Culm-nodes glabrous, or pubescent. Leaf-sheaths hirsute; with tubercle-based hairs. Ligule an eciliate membrane; 0.75 mm long. Leaf-blades linear, or lanceolate; 2–5 cm long; 2–3 mm wide. Leaf-blade midrib keeled beneath. Leaf-blade surface hirsute; sparsely hairy; hairy on both sides; with tubercle-based hairs. Leaf-blade margins scabrous. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence composed of racemes; subtended by an inflated leaf-sheath. Peduncle 10 cm long; pilose above.

Racemes 2; paired; 3–4 cm long. Rhachis fragile at the nodes; subterete; ciliate on margins. Rhachis hairs tawny; 2–4.5 mm long. Rhachis internodes linear; 1.5 mm long.

Spikelets appressed; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels adnate at the base to lower glume of sessile spikelet; linear; 2.5 mm long; ciliate; with tawny hairs; with 4.5 mm long hairs.

STERILE SPIKELETS Companion sterile spikelets represented by barren pedicels.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; dorsally compressed; truncate; 4.5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus base obtuse; attached transversely.

GLUMES Glumes dissimilar; reaching apex of florets; firmer than fertile lemma. Lower glume oblong; 0.9 length of spikelet; coriaceous; dark brown; without keels; 7 -veined. Lower glume primary vein extending to apex. Lower glume lateral veins ribbed; excurrent. Lower glume surface scabrous; rough on veins. Lower glume apex erose; truncate. Upper glume oblong; 1 length of spikelet; chartaceous; dark brown; 3 -veined. Upper glume lateral veins all falling short of apex. Upper glume margins ciliate. Upper glume apex truncate.

FLORETS Basal sterile florets male, or barren; with palea. Lemma of lower sterile floret oblong; 4 mm long; hyaline; 0 -veined; without midvein; without lateral veins. Fertile lemma oblong; 4 mm long; hyaline; without keel; 1 -veined. Lemma surface scabrous. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 25–30 mm long overall; with twisted column. Column of lemma awn 14 mm long; hispidulous. Palea 3–3.25 mm long; hyaline; 0 -veined; without keels.

FLOWER Lodicules absent. Anthers 2; 2–2.5 mm long.

DISTRIBUTION Asia-tropical: Indo-China.

NOTES Andropogoneae. Bor 1992.

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