Muhlenbergia thurberi

HABIT Perennial; cushion forming. Rhizomes elongated; scaly. Culms erect, or geniculately ascending; 20–30 cm long. Culm-internodes distally glabrous. Leaves mostly basal. Leaf-sheaths smooth, or scaberulous; glabrous on surface. Ligule an eciliate membrane; 1 mm long; lacerate. Leaf-blades filiform; involute; 1–3 cm long; 0.5–1 mm wide.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear; 2–5 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; 3–4 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus pubescent.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; 2–3 mm long; 1 length of upper glume; membranous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume lanceolate; 2–3 mm long; 0.66–0.75 length of adjacent fertile lemma; membranous; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume apex acute.

FLORETS Fertile lemma lanceolate; 3–4 mm long; membranous; without keel; 3 -veined. Lemma surface pubescent; hairy below. Lemma margins ciliate; hairy below. Lemma apex acute; mucronate, or awned; 1 -awned. Principal lemma awn 0.5–1 mm long overall. Palea 0.9 length of lemma; 2 -veined. Palea surface pilose; hairy below.

FLOWER Lodicules 2; cuneate; fleshy. Anthers 3.

FRUIT Caryopsis with adherent pericarp; fusiform; 1.8–2.2 mm long.

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

NOTES Eragrostideae. Gr SW US 1994.

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