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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 aristidoides
HABIT Annual; caespitose. Culms geniculately ascending, or decumbent; slender; 6–50 cm long. Ligule a fringe of hairs. Leaf-blades flat, or conduplicate; 2–7 cm long; 1–2 mm wide. Leaf-blade surface pilose; sparsely hairy; hairy adaxially.
INFLORESCENCE Inflorescence composed of racemes.
Racemes 4–15; borne along a central axis; spreading, or deflexed; unilateral; 1.5–3.5 cm long; bearing few fertile spikelets; bearing 2–4 fertile spikelets on each. Central inflorescence axis 2.5–10 cm long; tip subulate. Rhachis deciduous from axis; flattened; pubescent on surface; terminating in a barren extension; extension bristle-like; extension 5–10 mm long. Spikelet packing broadside to rhachis. Raceme-bases linear; 1 mm long; shed with the raceme; acute, or pungent.
Spikelets appressed; solitary. Fertile spikelets sessile.
STERILE SPIKELETS Basal sterile spikelets rudimentary; 1 in number.
FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with diminished florets at the apex. Spikelets cuneate; laterally compressed; 6–8 mm long; falling entire; deciduous with accessory branch structures.
GLUMES Glumes similar; shorter than spikelet; thinner than fertile lemma; gaping. Lower glume lanceolate; 1.5–2 mm long; 0.3–0.4 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume primary vein scaberulous. Lower glume lateral veins absent. Lower glume apex acute, or acuminate. Upper glume lanceolate; 5–6 mm long; 0.7–0.8 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume primary vein scaberulous. Upper glume lateral veins absent. Upper glume apex acute, or acuminate.
FLORETS Fertile lemma lanceolate; 6–8 mm long; coriaceous; keeled; 3 -veined. Lemma surface pubescent. Lemma apex dentate; 3 -fid; mucronate; 3 -awned (mucros). Palea apex with excurrent keel veins. Rhachilla extension glabrous. Apical sterile florets 1 in number; barren; rudimentary. Apical sterile lemmas awned; 3 -awned. Apical sterile lemma awns equal; 2–6 mm long.
FRUIT Caryopsis with adherent pericarp; 2.5–3 mm long; light brown. Embryo 0.75 length of caryopsis.
DISTRIBUTION North America: southwest USA, south-central USA, and Mexico. South America: Caribbean, western South America, and southern South America.
NOTES Cynodonteae. Gould.
Please cite this publication as detailed in How to Cite Version: 3rd February 2016.
