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.

Mesosetum pittieri

HABIT Annual. Culms geniculately ascending, or decumbent, or prostrate; 15–50 cm long; 1 mm diam.; rooting from lower nodes. Ligule a fringe of hairs; 0.2–0.5 mm long. Leaf-blades 5–9 cm long; 3–5 mm wide. Leaf-blade margins cartilaginous.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 1; single; erect; unilateral; 3–7 cm long. Rhachis angular; 1 mm wide. Spikelet packing adaxial; regular; 2 -rowed.

Spikelets appressed; solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; laterally compressed; 5.5–6.2 mm long; falling entire. Spikelet callus oblong; incorporating lowest rhachilla internode with adnate lower glume; 0.5–1 mm long; glabrous; base truncate.

GLUMES Glumes dissimilar; reaching apex of florets; thinner than fertile lemma. Lower glume oblong; 4.9–5.5 mm long; 0.9 length of spikelet; chartaceous; 1-keeled; winged on keel; winged near apex; 3 -veined. Lower glume primary vein scabrous (above); ciliate (below). Lower glume apex truncate. Upper glume oblong; 5.5–6.2 mm long; 1 length of spikelet; chartaceous; 1-keeled; winged on keel; winged near apex; 5 -veined. Upper glume primary vein ciliate. Upper glume lateral veins ribbed. Upper glume surface rugose; rough above. Upper glume margins ciliate. Upper glume apex acute.

FLORETS Basal sterile florets barren; with palea. Lemma of lower sterile floret ovate; 5.5–6.2 mm long; 1 length of spikelet; membranous; 1-keeled; winged on keel (at apex); 5 -veined; ribbed; rugose; rough above; pilose; hairy below; hairy between veins; with dorsal tufts of hair; 1 hair tufts in all; ciliate on margins (in the middle); acute. Palea of lower sterile floret 0.66 length of lemma. Fertile lemma ovate; laterally compressed; 4.7–4.8 mm long; indurate; without keel; 5 -veined. Lemma surface granulose. Lemma margins flat. Lemma apex acute. Palea coriaceous.

FLOWER Anthers 3; 2 mm long.

FRUIT Caryopsis with adherent pericarp; obovoid. Embryo 0.5 length of caryopsis.

DISTRIBUTION North America: Mexico. South America: Mesoamericana.

NOTES Paniceae. Pohl.

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