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 purpurea

HABIT Perennial; mat forming. Stolons present. Culms 20–60 cm long. Ligule a ciliate membrane; 0.4–0.8 mm long. Leaf-blades straight; 1.5–3 mm wide.

INFLORESCENCE Inflorescence composed of racemes.

Racemes numerous; 30–50; borne along a central axis; unilateral; 0.5 cm long; bearing (1–)3–5(–7) fertile spikelets on each. Central inflorescence axis 12–20 cm long; tip subulate. Rhachis deciduous from axis; angular; terminating in a barren extension; extension subulate. Spikelet packing broadside to rhachis.

Spikelets appressed; solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with diminished florets at the apex. Spikelets cuneate; laterally compressed; 5–7 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes similar; shorter than spikelet, or reaching apex of florets; thinner than fertile lemma; gaping. Lower glume lanceolate; 3.5–4.5 mm long; 0.66 length of upper glume; membranous; purple; 1-keeled; 1 -veined. Lower glume primary vein smooth, or scaberulous. Lower glume lateral veins absent. Lower glume apex acuminate. Upper glume elliptic; 5–7 mm long; 1 length of adjacent fertile lemma; membranous; purple; 1-keeled; 1 -veined. Upper glume primary vein smooth, or scaberulous. Upper glume lateral veins absent. Upper glume apex acuminate.

FLORETS Fertile lemma ovate; 5–7 mm long; membranous; purple; keeled; 3 -veined. Lemma apex entire; acute; mucronate; 3 -awned (mucros). Rhachilla extension glabrous. Apical sterile florets 1 in number; barren; rudimentary, or oblong; 0–3 mm long. Apical sterile lemmas dentate; 3 -fid; awned; 1 -awned. Apical sterile lemma awns 1–5 mm long.

FLOWER Anthers 3; 3–4 mm long; purple.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION North America: Mexico.

NOTES Cynodonteae. Gould.

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