Muhlenbergia tenuissima

HABIT Annual. Culms decumbent; 7–30 cm long. Culm-internodes antrorsely scabrous. Lateral branches ample. Leaf-sheaths glabrous on surface, or puberulous. Ligule an eciliate membrane; 0.8–1.2 mm long. Leaf-blades conduplicate; 3–7 cm long; 0.5–1 mm wide. Leaf-blade surface puberulous; hairy adaxially.

INFLORESCENCE Inflorescence a panicle. Peduncle 1–3 cm long.

Panicle open; oblong; effuse; 4–8 cm long; 1–2 cm wide. Panicle branches capillary.

Spikelets spreading; solitary. Fertile spikelets pedicelled. Pedicels filiform; tip widened.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 1.7–1.9 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus glabrous.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume ovate; 0.5–0.7 mm long; 0.6–0.7 length of upper glume; membranous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex acuminate. Upper glume ovate; 0.8–1 mm long; 0.5 length of adjacent fertile lemma; membranous; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume apex acuminate.

FLORETS Fertile lemma lanceolate; 1.7–1.9 mm long; membranous; without keel; 3 -veined. Lemma margins ciliate. Lemma apex acuminate; awned; 1 -awned. Principal lemma awn 6–11 mm long overall. Palea 1 length of lemma; 2 -veined. Palea keels ciliolate.

FLOWER Lodicules 2; cuneate; fleshy. Anthers 3; 0.5–0.6 mm long; purple.

FRUIT Caryopsis with adherent pericarp; fusiform.

DISTRIBUTION North America: Mexico. South America: Mesoamericana and western South America.

NOTES Eragrostideae. Fl Costa Rica 1994.

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