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 trinitensis

HABIT Perennial; caespitose. Culms erect; slender; 20–30 cm long. Culm-internodes distally glabrous. Culm-nodes bearded. Lateral branches lacking. Leaf-sheaths mostly shorter than adjacent culm internode; keeled; outer margin hairy. Leaf-sheath oral hairs ciliate. Ligule an eciliate membrane; 0.7 mm long; pilose on abaxial surface. Leaf-blades 2–5 cm long; 1.5–3 mm wide. Leaf-blade surface pilose; with tubercle-based hairs.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 1; single; straight; unilateral; 1.5(–8) cm long. Rhachis narrowly winged; folded longitudinally to embrace spikelets; 2 mm wide; glabrous on surface; tuberculate on margins; setose on margins; terminating in a barren extension; extension flattened. Rhachis hairs white, or 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; 2.5 mm long; 0.7 mm wide; falling entire.

GLUMES Glumes one the lower absent or obscure, or two; dissimilar; shorter than spikelet; thinner than fertile lemma. Lower glume ovate; 0–0.3(–1.2) mm long; 0.1(–0.5) length of spikelet; hyaline; without keels; 0–1 -veined. Lower glume lateral veins absent. Lower glume surface glabrous, or puberulous. Lower glume apex acute. Upper glume elliptic; 0.33 length of spikelet; hyaline; without keels; 2–3 -veined. Upper glume primary vein absent, or distinct. Upper glume margins pubescent. Upper glume apex emarginate, or truncate.

FLORETS Basal sterile florets barren; with palea. Lemma of lower sterile floret elliptic; 1 length of spikelet; coriaceous; sulcate and readily splitting into two halves; with conspicuous apical hairs; pubescent on midvein (above); acute. Palea of lower sterile floret becoming indurate on flanks at maturity. Fertile lemma elliptic; 2 mm long; coriaceous; without keel. Lemma surface papillose and striate; with conspicuous apical hairs. Lemma margins involute; ciliate; hairy above. Lemma apex acute. Palea coriaceous. Palea apex glabrous, or ciliate.

DISTRIBUTION South America: Mesoamericana, Caribbean, northern South America, and Brazil.

NOTES Paniceae. Burman 2000.

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