Muhlenbergia richardsonis

HABIT Perennial; mat forming. Rootstock evident. Rhizomes short; scaly. Culms erect, or geniculately ascending; 5–60 cm long. Culm-internodes striate; scaberulous (nodulose). Leaf-sheaths glabrous on surface. Ligule an eciliate membrane; 1.5–2(–3) mm long; erose. Leaf-blades flat, or involute; 1–5 cm long; 1–1.5 mm wide. Leaf-blade surface smooth, or scaberulous; rough abaxially; puberulous; hairy adaxially.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear; interrupted; 2–10 cm long. Primary panicle branches appressed.

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. Floret callus glabrous.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume oblong; 1–1.5 mm long; 1 length of upper glume; membranous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex obtuse, or acute. Upper glume oblong; 1–1.5 mm long; 0.4–0.5 length of adjacent fertile lemma; membranous; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume apex obtuse, or acute.

FLORETS Fertile lemma lanceolate; 2.5–3 mm long; membranous; without keel; 3 -veined. Lemma surface scabrous; rough above. Lemma apex acute, or acuminate; muticous, or mucronate. Palea 0.9 length of lemma; 2 -veined. Palea surface scaberulous.

FLOWER Lodicules 2; cuneate; fleshy. Anthers 3; 1.2–1.5 mm long.

FRUIT Caryopsis with adherent pericarp; fusiform; 1.2 mm long; light brown.

DISTRIBUTION North America: Subarctic, western Canada, eastern Canada, northwest USA, north-central USA, northeast 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.