Muhlenbergia rigens

HABIT Perennial; caespitose. Culms erect; 60–100 cm long. Ligule an eciliate membrane, or a ciliolate membrane; 1–3 mm long. Leaf-blades involute; 15–50 cm long; 1–4 mm wide; stiff. Leaf-blade surface ribbed; scabrous; rough adaxially. Leaf-blade apex filiform.

INFLORESCENCE Inflorescence a panicle.

Panicle spiciform; linear; continuous, or interrupted; 30–60 cm long. Primary panicle branches 1–4 cm long.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; compressed slightly; 2.5–3.5 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; 2–3 mm long; 1 length of upper glume; membranous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume surface scabrous. Lower glume apex obtuse, or acute. Upper glume lanceolate; 2–3 mm long; 0.8 length of adjacent fertile lemma; membranous; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume surface scabrous. Upper glume apex obtuse, or acute.

FLORETS Fertile lemma elliptic; 2.5–3.5 mm long; membranous; without keel; 3 -veined. Lemma midvein pubescent; hairy above. Lemma surface scaberulous; rough above. Lemma margins pubescent; hairy below. Lemma apex obtuse, or acute; muticous, or mucronate. Palea 1 length of lemma; 2 -veined. Palea surface scabrous.

FLOWER Lodicules 2; cuneate; fleshy. Anthers 3; 1.5–1.7 mm long.

FRUIT Caryopsis with adherent pericarp; fusiform; 2 mm long.

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

NOTES Eragrostideae. WDC.

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