GrassBase - The Online World Grass Flora


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

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

Leptothrium rigidum

HABIT Perennial; short-lived; caespitose. Cataphylls evident. Culms geniculately ascending; 15–50 cm long; wiry. Leaves cauline. Leaf-sheaths loose. Leaf-sheath auricles erect. Ligule a fringe of hairs. Leaf-blades linear to lanceolate; flat, or involute; 15–30 cm long; 0.5–2 mm wide.

INFLORESCENCE Inflorescence composed of racemes.

Racemes numerous; borne along a central axis; in a multilateral false spike; spreading; cuneate; bearing few fertile spikelets; bearing 1 fertile spikelets on each, or 2 fertile spikelets on each. Central inflorescence axis 5–10 cm long. Rhachis obsolete; deciduous from axis. Raceme-bases cuneate; 1.5–2.5 mm long; pilose; hairy on margins.

Spikelets solitary, or in pairs. Fertile spikelets sessile; 1–2 in the cluster; subequal, or the upper smaller (lower glume of one spikelet usually enlarged).

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets linear to lanceolate; laterally compressed; 6–7 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes dissimilar; with lower wider than upper; exceeding apex of florets; firmer than fertile lemma. Lower glume linear to lanceolate; 4–7 mm long; 1–1.3 length of upper glume; coriaceous; without keels; (1–)3 -veined. Lower glume surface convex, or flat; smooth, or scabrous. Lower glume margins ciliolate. Lower glume apex attenuate to caudate. Upper glume linear to lanceolate; 4–6 mm long; 3–4 length of adjacent fertile lemma; coriaceous; without keels; 3 -veined. Upper glume primary vein ciliate. Upper glume surface scabrous. Upper glume apex caudate, or acuminate.

FLORETS Fertile lemma ovate; 1–1.5 mm long; hyaline; without keel; 1 -veined. Lemma margins ciliolate; hairy above. Lemma apex obtuse. Palea 0.6–0.8 length of lemma; hyaline; 0 -veined; without keels.

FLOWER Anthers 3; 0.6–0.8 mm long.

FRUIT Caryopsis with adherent pericarp; fusiform; laterally compressed; biconvex; 2 mm long. Embryo 0.5 length of caryopsis.

DISTRIBUTION South America: Caribbean, northern South America, and western South America.

NOTES Cynodonteae. TB.

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