Isachne arfakensis

HABIT Perennial. Culms geniculately ascending, or rambling; 65–110 cm long. Culm-internodes smooth; distally glabrous. Lateral branches ample. Leaf-sheaths mostly shorter than adjacent culm internode; glabrous on surface; outer margin hairy. Ligule a fringe of hairs; 2 mm long. Leaf-blades lanceolate; 5–15 cm long; 6–12 mm wide. Leaf-blade surface scabrous; rough adaxially; pubescent; hairy abaxially. Leaf-blade margins scabrous.

INFLORESCENCE Inflorescence a panicle. Peduncle antrorsely scabrous above.

Panicle open; oblong, or ovate; 8–20 cm long. Primary panicle branches ascending. Panicle axis scabrous. Panicle branches stiff; scabrous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels scabrous.

FERTILE SPIKELETS Spikelets comprising 2 fertile florets; without rhachilla extension. Spikelets orbicular; dorsally compressed; 1.5–1.8 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes terete.

GLUMES Glumes deciduous; similar; reaching apex of florets; thinner than fertile lemma. Lower glume ovate; 1.5–1.8 mm long; 1 length of upper glume; 1 length of spikelet; membranous; without keels; 7 -veined. Lower glume surface smooth, or asperulous; glabrous, or hispidulous; hairy at apex. Lower glume apex obtuse. Upper glume ovate; 1.5–1.8 mm long; 1 length of adjacent fertile lemma; membranous; without keels; 7 -veined. Upper glume surface smooth, or asperulous; glabrous, or hispidulous; hairy generally. Upper glume apex obtuse.

FLORETS Fertile lemma elliptic, or orbicular; 1.5–1.8 mm long; coriaceous; without keel. Lemma surface glabrous, or puberulous. Lemma margins involute. Lemma apex obtuse. Palea coriaceous; 2 -veined.

DISTRIBUTION Asia-tropical: Malesia and Papuasia.

NOTES Isachneae. Reeder 1997.

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