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 johnstonii

HABIT Perennial; caespitose. Rootstock evident. Culms 10–30 cm long. Ligule a fringe of hairs. Leaf-blades curved; involute; 1–2 mm wide; stiff. Leaf-blade apex hardened.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 6–12; borne along a central axis; cuneate; unilateral; 0.8–1.5 cm long; bearing 7–11 fertile spikelets on each. Central inflorescence axis 7–10 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; reaching apex of florets; thinner than fertile lemma; gaping. Lower glume lanceolate; 2–3 mm long; 0.4–0.5 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume surface glabrous. Lower glume apex acute to setaceously attenuate. Upper glume lanceolate; 5–7 mm long; 1 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume surface glabrous, or pubescent; hairy at base. Upper glume apex acute to setaceously attenuate.

FLORETS Fertile lemma ovate; 5–7 mm long; coriaceous; keeled; 3 -veined. Lemma apex dentate; 3 -fid; with central lobe bidentate; awned; 3 -awned. Principal lemma awn 2–3 mm long overall. Lateral lemma awns arising on margin of lemma; 2–3 mm long; subequal to principal. Rhachilla extension glabrous. Apical sterile florets 1–2 in number; barren; rudimentary. Apical sterile lemmas awned; 3 -awned. Apical sterile lemma awns 2–3 mm long.

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.