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 disticha

HABIT Annual. Stolons absent, or present. Culms decumbent, or rambling; weak; 40–100 cm long. Ligule a fringe of hairs; 0.5 mm long. Leaf-blades 3–6 mm wide. Leaf-blade surface glabrous, or pilose.

INFLORESCENCE Inflorescence composed of racemes.

Racemes numerous; 15–45; borne along a central axis; unilateral; 1.5 cm long; bearing few fertile spikelets; bearing 3–4 fertile spikelets on each. Central inflorescence axis 3–12 cm long; tip subulate. Rhachis deciduous from axis; flattened; terminating in a barren extension; extension subulate. Spikelet packing broadside to rhachis.

Spikelets appressed; solitary. Fertile spikelets sessile.

STERILE SPIKELETS Basal sterile spikelets well-developed; 1–2 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 subulate; 3–4 mm long; 0.6–0.7 length of upper glume; membranous; 1 -veined. Lower glume lateral veins absent. Upper glume lanceolate; 4.5–7 mm long; 1 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume apex acuminate.

FLORETS Fertile lemma ovate; 4.5–7 mm long; coriaceous; keeled; 3 -veined. Lemma apex dentate; 3 -fid; awned; 3 -awned. Principal lemma awn 0.5–1 mm long overall. Lateral lemma awns arising on margin of lemma; 1–1.5 mm long; subequal to principal. Rhachilla extension glabrous. Apical sterile florets 1 in number; barren; rudimentary. Apical sterile lemmas awned; 1 -awned, or 3 -awned. Apical sterile lemma awns unequal; 6–10 mm long.

FLOWER Anthers orange, or red.

FRUIT Caryopsis with adherent pericarp.

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

NOTES Cynodonteae. Gould.

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