Muhlenbergia filiformis

HABIT Annual; caespitose; clumped loosely. Culms erect, or geniculately ascending; slender; 5–20 cm long; without nodal roots, or rooting from lower nodes. Leaf-sheaths smooth, or scaberulous; glabrous on surface. Ligule an eciliate membrane; 1–2 mm long; erose; obtuse. Leaf-blades 1–5 cm long; 1–2 mm wide. Leaf-blade surface scabrous; rough adaxially, or on both sides.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear; interrupted; 2–6 cm long; bearing few spikelets. Primary panicle branches appressed.

Spikelets solitary. Fertile spikelets pedicelled.

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

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume oblong; 0.6–1 mm long; 1 length of upper glume; membranous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex entire, or erose; obtuse. Upper glume oblong; 0.6–1 mm long; 0.33–0.5 length of adjacent fertile lemma; membranous; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume apex entire, or erose; obtuse.

FLORETS Fertile lemma lanceolate; 2 mm long; membranous; without keel; 3 -veined. Lemma surface scaberulous; rough above. Lemma apex acute; muticous, or mucronate. Palea 1 length of lemma; 2 -veined. Palea surface scaberulous (above).

FLOWER Lodicules 2; cuneate; fleshy. Anthers 3; 0.6–0.9 mm long; purple.

FRUIT Caryopsis with adherent pericarp; fusiform; 1–1.2 mm long; dark brown.

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