Muhlenbergia arenacea

HABIT Perennial; mat forming. Rhizomes elongated. Culms decumbent; 10–20(–40) cm long. Culm-internodes striate; antrorsely scabrous. Leaves mostly basal. Leaf-sheaths mostly shorter than adjacent culm internode; without keel. Leaf-sheath auricles erect; 1–2 mm long. Ligule an eciliate membrane; 0.5 mm long; lacerate. Leaf-blades flat, or conduplicate, or involute; 1–3(–6) cm long; 0.5–1.5 mm wide. Leaf-blade midrib widened. Leaf-blade margins cartilaginous. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle.

Panicle open; ovate; effuse; 5–15 cm long; 4–12 cm wide.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels filiform; flexuous.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 1.5–2 mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes persistent; similar; shorter than spikelet; similar to fertile lemma in texture. Lower glume lanceolate; 0.9–1.3 mm long; 1 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume surface smooth to scabrous. Lower glume apex acute; muticous, or mucronate. Upper glume lanceolate; 0.9–1.3 mm long; 0.5 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume surface smooth to scabrous. Upper glume apex acute; muticous, or mucronate.

FLORETS Fertile lemma lanceolate; 1.5–2 mm long; membranous; purple; keeled; 3 -veined. Lemma apex obtuse; muticous. Palea 1 length of lemma; 2 -veined.

FLOWER Lodicules 2; cuneate; fleshy.

FRUIT Caryopsis with adherent pericarp; fusiform.

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

NOTES Eragrostideae. Gould.

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