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.

Muhlenbergia mexicana

HABIT Perennial. Rhizomes elongated. Culms 30–90 cm long. Culm-internodes smooth; distally pubescent. Lateral branches ample; arising from upper culm. Ligule an eciliate membrane; 0.4–1 mm long. Leaf-blades 5–15 cm long; 2–6 mm wide. Leaf-blade surface glabrous.

INFLORESCENCE Inflorescence a panicle; terminal and axillary. Peduncle 2–12 cm long.

Panicle contracted; linear, or lanceolate; interrupted; dense; 7–21 cm long; 0.2–1 cm wide. Primary panicle branches appressed; bearing spikelets almost to the base.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels linear.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 2–4(–4.4) mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus pilose.

GLUMES Glumes persistent; similar; shorter than spikelet, or reaching apex of florets, or exceeding apex of florets; similar to fertile lemma in texture. Lower glume lanceolate; 2–4.4 mm long; 1 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume primary vein scabrous. Lower glume lateral veins absent. Lower glume apex attenuate; awned; 1 -awned. Lower glume awn 0.5–1.5 mm long. Upper glume lanceolate; 2–4.4 mm long; 0.9–1.5 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume primary vein scabrous. Upper glume lateral veins absent. Upper glume apex attenuate; awned; 1 -awned. Upper glume awn 0.5–1.5 mm long.

FLORETS Fertile lemma lanceolate; 1.4–3.4 mm long; membranous; keeled; 3 -veined. Lemma apex acute; muticous, or mucronate. Palea 1 length of lemma; 2 -veined.

FLOWER Lodicules 2; cuneate; fleshy. Anthers 3; 0.3–0.5 mm long; yellow.

FRUIT Caryopsis with adherent pericarp; fusiform.

DISTRIBUTION North America: western Canada, eastern Canada, northwest USA, north-central USA, northeast USA, southwest USA, south-central USA, and southeast USA.

NOTES Eragrostideae. Gould.

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