Muhlenbergia expansa

HABIT Perennial; caespitose; clumped densely. Butt sheaths persistent and investing base of culm; with fibrous dead sheaths. Culms erect; slender; 60–100 cm long. Culm-internodes distally glabrous. Leaf-sheaths without keel; glabrous on surface. Ligule an eciliate membrane; 2–4(–5) mm long. Leaf-blades curved; flat, or involute; 30–50 cm long; 2–3 mm wide.

INFLORESCENCE Inflorescence a panicle.

Panicle open; oblong; effuse; 20–30(–60) cm long; 4–7(–10) cm wide. Primary panicle branches spreading. Panicle branches flexuous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels filiform.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 3.5–4(–5) mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus pubescent.

GLUMES Glumes persistent; similar; shorter than spikelet; similar to fertile lemma in texture. Lower glume lanceolate; 2.5–3.5 mm long; 1 length of upper glume; membranous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute, or acuminate; muticous, or mucronate. Upper glume lanceolate; 2.5–3.5 mm long; 0.5–0.66 length of adjacent fertile lemma; membranous; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume apex acute, or acuminate; muticous, or mucronate.

FLORETS Fertile lemma lanceolate; 3.5–4(–5) mm long; membranous; light brown; without keel; 3 -veined. Lemma surface scaberulous; rough above. Lemma apex acuminate; awned; 1 -awned. Principal lemma awn 0.5–1(–1.5) mm long overall. Palea 1 length of lemma; 2 -veined.

FLOWER Lodicules 2; cuneate; fleshy. Anthers 3.

FRUIT Caryopsis with adherent pericarp; fusiform.

DISTRIBUTION North America: south-central USA and southeast USA.

NOTES Eragrostideae. Gould.

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