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.

Thrasya auricoma

HABIT Perennial; caespitose. Culms erect; 35–40 cm long. Culm-nodes bearded. Leaf-sheaths mostly shorter than adjacent culm internode, or longer than adjacent culm internode; keeled; hirsute; with tubercle-based hairs; outer margin hairy. Ligule an eciliate membrane; 1.5–2 mm long. Leaf-blades conduplicate; 6–20 cm long; 1 mm wide. Leaf-blade surface pilose; hairy on both sides. Leaf-blade margins tuberculate-ciliate. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence composed of racemes. Peduncle glabrous, or pilose above.

Racemes 1; single; arcuate; unilateral; 1–4 cm long. Rhachis broadly winged; folded longitudinally to embrace spikelets; 3–4 mm wide; pilose on surface; tuberculate on margins; ciliate on margins; terminating in a barren extension; extension flattened. Rhachis hairs yellow. Spikelet packing alternately adaxial and abaxial; regular; 1 -rowed.

Spikelets pectinate; in pairs. Fertile spikelets sessile and pedicelled; 2 in the cluster. Pedicels fused to internode; united wholly.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; 2 mm long; 0.6 mm wide; falling entire. Spikelet callus square; 0.5 mm long; pubescent.

GLUMES Glumes one the lower absent or obscure; shorter than spikelet; thinner than fertile lemma. Upper glume elliptic; 0.8–0.9 length of spikelet; membranous; without keels; 2 -veined. Upper glume surface glabrous, or pilose; hairy at apex. Upper glume apex erose; truncate, or acute.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret elliptic, or oblong; 1 length of spikelet; coriaceous; 4 -veined; sulcate and readily splitting into two halves; ciliate on margins (above); acute. Palea of lower sterile floret becoming indurate on flanks at maturity. Fertile lemma elliptic; 1.7 mm long; coriaceous; without keel. Lemma surface striate; with conspicuous apical hairs. Lemma margins involute. Lemma apex acute. Palea coriaceous.

FLOWER Lodicules 2; fleshy; truncate. Anthers 3.

DISTRIBUTION South America: Brazil.

NOTES Paniceae. Burman 1993.

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