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.

Mesosetum exaratum

HABIT Perennial; caespitose. Butt sheaths pilose. Culms erect; slender; 8–35 cm long; 0.5–1 mm diam. Culm-nodes pubescent. Leaves mostly basal. Leaf-sheaths glabrous on surface. Ligule a fringe of hairs; 0.5–0.8 mm long. Leaf-blades filiform; convolute; 3–10 cm long; 0.5–1 mm wide. Leaf-blade apex attenuate; hardened.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 1; single; unilateral; 2–3.5 cm long; bearing few fertile spikelets; bearing 5–10 fertile spikelets on each. Rhachis subterete; glabrous on margins. Spikelet packing adaxial.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels free, or fused to internode; united wholly, or below; oblong; 1 mm long; ciliate; hairy at tip.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets obovate; laterally compressed; 3.8–4 mm long; falling entire. Spikelet callus pubescent.

GLUMES Glumes dissimilar; shorter than spikelet; firmer than fertile lemma. Lower glume oblong; 2.8–3.2 mm long; 0.7–0.8 length of spikelet; membranous; much thinner above (and along midline); 1-keeled; 3–5 -veined. Lower glume margins ciliate (above). Lower glume hairs white; 2 mm long. Lower glume apex obtuse, or acute. Upper glume lanceolate; 3.5–3.8 mm long; 0.9–1 length of spikelet; membranous; without keels; 5 -veined. Upper glume surface pilose; hairy above. Upper glume margins ciliate. Upper glume hairs white. Upper glume apex acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; 1 length of spikelet; membranous; 3–5 -veined; with marginal tufts of hair; 2 hair tufts in all; acute. Fertile lemma ovate; dorsally compressed; 3–3.3 mm long; membranous; much thinner on margins; without keel; 5 -veined. Lemma lateral veins obscure. Lemma surface glabrous. Lemma margins flat. Lemma apex acute. Palea membranous; without keels.

FLOWER Anthers 3; purple.

FRUIT Hilum linear; 1 length of caryopsis.

DISTRIBUTION South America: Brazil.

NOTES Paniceae. Filgueiras.

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