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 wrightii

HABIT Perennial; caespitose; clumped densely. Rootstock evident. Culms erect, or geniculately ascending; 15–60 cm long; wiry; 3–5 -noded. Culm-internodes distally pubescent. Leaf-sheaths keeled; smooth, or scaberulous; glabrous on surface. Ligule a ciliolate membrane; 0.5–1 mm long; obtuse. Leaf-blades erect, or ascending; flat, or conduplicate; 3–6 cm long; 1–3 mm wide. Leaf-blade midrib conspicuous. Leaf-blade surface puberulous; hairy adaxially. Leaf-blade margins cartilaginous. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle.

Panicle spiciform; linear; interrupted; 5–10(–15) cm long. Panicle branches bearing congested spikelets.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 2.5–3 mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume oblong; 0.5–1 mm long; 1 length of upper glume; membranous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex obtuse, or acute; awned; 1 -awned. Lower glume awn 0.5–0.8 mm long. Upper glume oblong; 0.5–1 mm long; 0.2–0.25 length of adjacent fertile lemma; membranous; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume apex obtuse, or acute; awned; 1 -awned. Upper glume awn 0.5–0.8 mm long.

FLORETS Fertile lemma lanceolate; 2.5–3 mm long; membranous; dark green, or grey; without keel; 3 -veined. Lemma midvein pubescent; hairy below. Lemma margins pubescent; hairy below. Lemma apex acuminate; muticous, or mucronate, or awned; 1 -awned. Principal lemma awn 0.3–0.5 mm long overall. Palea 1 length of lemma; 2 -veined. Palea surface pubescent; hairy on back; hairy below.

FLOWER Lodicules 2; cuneate; fleshy. Anthers 3; 1 mm long; green.

FRUIT Caryopsis with adherent pericarp; fusiform.

DISTRIBUTION North America: northwest USA, southwest USA, south-central USA, and Mexico.

NOTES Eragrostideae. Gr Baja Cal 1994.

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