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.

Bouteloua rigidiseta

HABIT Perennial; caespitose. Culms 10–50 cm long. Ligule a fringe of hairs. Leaf-blades flat, or involute; 4–12(–17) cm long; 1–2 mm wide. Leaf-blade surface pilose; sparsely hairy.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 7–10; borne along a central axis; spreading; cuneate; unilateral; 0.8–1.6 cm long; bearing few fertile spikelets; bearing 3–5 fertile spikelets on each. Central inflorescence axis 3–6 cm long. Rhachis deciduous from axis; angular; pilose on surface; terminating in a barren extension; extension a forked bristle. Spikelet packing broadside to rhachis.

Spikelets ascending; solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with diminished florets at the apex. Spikelets cuneate; laterally compressed; 2.5–4 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes similar; reaching apex of florets; thinner than fertile lemma; gaping. Lower glume linear; 2–3.5 mm long; 0.75 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acuminate. Upper glume lanceolate; 2.5–4 mm long; 1 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume primary vein conspicuous; ciliate. Upper glume lateral veins absent. Upper glume apex dentate; 2 -fid; awned; 1 -awned. Upper glume awn 1–2.5 mm long.

FLORETS Fertile lemma ovate; 2.5–4 mm long; coriaceous; keeled; 3 -veined. Lemma surface glabrous, or puberulous. Lemma apex dentate; 3 -fid; with central lobe bidentate; awned; 3 -awned. Principal lemma awn from a sinus; 1.5–2 mm long overall. Lateral lemma awns arising on apex of lobes; 1 mm long; shorter than principal. Rhachilla extension glabrous. Apical sterile florets 1 in number; barren; rudimentary. Apical sterile lemmas awned; 3 -awned. Apical sterile lemma awns 5–10 mm long.

FRUIT Caryopsis with adherent pericarp; obovoid. Embryo 0.66 length of caryopsis.

DISTRIBUTION North America: north-central USA, south-central USA, and Mexico.

NOTES Cynodonteae. Gould.

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