GrassBase - The Online World Grass Flora

Descriptions

W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Oplismenus compositus

HABIT Perennial. Culms prostrate; 15–150 cm long; rooting from lower nodes. Leaf-sheaths pilose. Ligule a ciliate membrane. Leaf-blade base asymmetrical. Leaf-blades lanceolate, or ovate; 2–16 cm long; 8–35 mm wide. Leaf-blade venation with obscure cross veins. Leaf-blade apex acuminate, or acute (bluntly).

INFLORESCENCE Inflorescence composed of racemes.

Racemes 4–12; borne along a central axis; unilateral; 2.5–11 cm long (lowest). Central inflorescence axis 5–25 cm long. Rhachis angular; glabrous on surface, or pilose on surface. Spikelet packing lax; regular; 2 -rowed.

Spikelets in pairs. Fertile spikelets sessile and pedicelled; 2 in the cluster; subequal, or the lower smaller. Pedicels oblong.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 2.5–4 mm long; falling entire.

GLUMES Glumes similar, or dissimilar; shorter than spikelet; thinner than fertile lemma. Lower glume ovate; 1 length of upper glume; 0.5–0.75 length of spikelet; herbaceous; 1-keeled; 5 -veined. Lower glume surface glabrous, or pubescent. Lower glume apex acute; awned; 1 -awned. Lower glume awn 3–10 mm long; viscid. Upper glume ovate; herbaceous; 1-keeled; 5–7 -veined. Upper glume surface glabrous, or pubescent. Upper glume apex obtuse; muticous, or awned. Upper glume awn 0–4 mm long.

FLORETS Basal sterile florets barren; with palea, or without significant palea. Lemma of lower sterile floret ovate; 1 length of spikelet; membranous; 1-keeled; 7–11 -veined; glabrous, or pubescent; emarginate; mucronate. Fertile lemma oblong; dorsally compressed; 2–2.5 mm long; coriaceous; shiny; without keel; 7 -veined. Lemma margins involute. Lemma apex acute; laterally pinched. Palea involute; coriaceous; without keels.

FRUIT Hilum linear; 0.5 length of caryopsis.

DISTRIBUTION Africa: northeast tropical, east tropical, southern tropical, south, and western Indian ocean. Asia-temperate: western Asia, Arabia, China, and eastern Asia. Asia-tropical: India, Indo-China, Malesia, and Papuasia. Australasia: Australia. Pacific: southwestern, south-central, northwestern, and north-central. North America: Mexico. South America: Mesoamericana, northern South America, and western South America.

NOTES Paniceae. SAR 2002.

ADDITIONAL CHARACTERS Spikelet pairs 4–12mm apart.

Please cite this publication as detailed in How to Cite Version: 27th January 2014.