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 compressum

HABIT Annual. Culms decumbent; 20–45 cm long; without nodal roots, or rooting from lower nodes. Culm-nodes pubescent. Leaf-sheaths glabrous on surface, or pubescent; outer margin hairy. Ligule a fringe of hairs; 1 mm long. Leaf-blades 3–13 cm long; 3–6 mm wide. Leaf-blade surface glabrous, or pubescent; hairy on both sides. Leaf-blade margins cartilaginous; tuberculate-ciliate.

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

Racemes 1; single; unilateral; 5–6 cm long. Rhachis broadly winged; foliaceous; 2–2.2 mm wide; ciliate on margins. Spikelet packing adaxial; crowded.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels oblong.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; laterally compressed; 5–6 mm long; falling entire. Spikelet callus pubescent.

GLUMES Glumes dissimilar; shorter than spikelet; thinner than fertile lemma. Lower glume lanceolate; 4.5–5 mm long; 0.8–0.9 length of spikelet; chartaceous; 1-keeled; 3 -veined. Lower glume surface scabrous. Lower glume apex dentate; 2 -fid; awned; 1 -awned. Lower glume awn 5–12 mm long. Upper glume lanceolate; 4.8–5 mm long; 0.8–0.9 length of spikelet; membranous; without keels; 5 -veined. Upper glume surface scabrous; with marginal tufts of hair. Upper glume margins ciliate. Upper glume apex acute; mucronate, or awned; 1 -awned. Upper glume awn 0.5–1 mm long.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret oblong; 1 length of spikelet; membranous; 5 -veined; with marginal tufts of hair; 2 hair tufts in all; entire, or dentate; 3 -fid; obtuse. Fertile lemma ovate; dorsally compressed; 3.3 mm long; coriaceous; shiny; keeled; lightly keeled; 5 -veined. Lemma surface smooth. Lemma margins flat. Lemma apex acute. Palea coriaceous; 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.