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.

Bouteloua americana

HABIT Perennial; persisting, or short-lived. Culms decumbent, or rambling; weak; 8–100 cm long. Ligule a fringe of hairs. Leaf-blades involute; 2–4 mm wide. Leaf-blade surface glabrous, or hirsute; sparsely hairy; hairy on both sides. Leaf-blade margins glabrous, or tuberculate-ciliate; hairy at base.

INFLORESCENCE Inflorescence composed of racemes; exserted, or embraced at base by subtending leaf.

Racemes 5–12; borne along a central axis; unilateral; 1–5 cm long; bearing 5–10 fertile spikelets on each. Central inflorescence axis 5–20 cm long; tip filiform. Rhachis deciduous from axis; angular; terminating in a barren extension; extension subulate. Spikelet packing broadside to rhachis; lax.

Spikelets appressed; solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with diminished florets at the apex. Spikelets elliptic; laterally compressed; 4.5–7 mm long; falling entire; deciduous with accessory branch structures; readily shedding fertile florets. Floret callus bearded.

GLUMES Glumes similar; shorter than spikelet; thinner than fertile lemma; gaping. Lower glume lanceolate; 3–4.5 mm long; 0.9 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume surface hispidulous. Lower glume apex acute, or acuminate; muticous, or mucronate. Upper glume lanceolate; 3.5–5 mm long; 0.7–0.8 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume surface hispidulous. Upper glume apex acute, or acuminate; muticous, or mucronate.

FLORETS Fertile lemma ovate; 4.5–7 mm long; cartilaginous; shiny; keeled; 3 -veined. Lemma surface glabrous, or puberulous; hairy in lines. Lemma apex dentate; 3 -fid; awned; 3 -awned. Principal lemma awn 2.5–3 mm long overall. Lateral lemma awns arising on margin of lemma; 0.5–1 mm long; shorter than principal. Palea apex awned. Rhachilla extension glabrous. Apical sterile florets 1 in number; barren; rudimentary. Apical sterile lemmas awned; 3 -awned. Apical sterile lemma awns equal; 9 mm long.

FRUIT Caryopsis with adherent pericarp; ovoid; 3–3.5 mm long.

DISTRIBUTION North America: Mexico. South America: Mesoamericana, Caribbean, northern South America, western South America, and Brazil.

NOTES Cynodonteae. Gould.

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