Muhlenbergia nigra

HABIT Perennial; caespitose; clumped densely. Culms erect; 90–100 cm long; 2–3 mm diam. Culm-internodes scaberulous. Culm-nodes glabrous. Lateral branches lacking. Ligule an eciliate membrane; 7–20 mm long; white; entire, or lacerate; acute. Leaf-blades involute; 30–50 cm long; 2–3 mm wide. Leaf-blade surface ribbed; scaberulous.

INFLORESCENCE Inflorescence a panicle. Peduncle antrorsely scabrous above.

Panicle spiciform; linear; tapering above and tapering below; 10–14 cm long; 0.5–1 cm wide. Panicle axis puberulous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels reduced to a stump; puberulous.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 6–7 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus pubescent.

GLUMES Glumes persistent; similar; reaching apex of florets, or exceeding apex of florets. Lower glume lanceolate; 6–7 mm long; 1 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume surface asperulous. Lower glume apex acuminate. Upper glume lanceolate; 6–7 mm long; 1 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume primary vein scaberulous. Upper glume lateral veins absent. Upper glume apex acuminate.

FLORETS Fertile lemma ovate; 6–6.5 mm long; membranous; without keel; 3 -veined. Lemma surface scaberulous. Lemma apex acuminate; muticous, or mucronate. Palea 0.9 length of lemma; 2 -veined.

FLOWER Lodicules 2; cuneate; fleshy. Anthers 3; 2.5–3 mm long.

FRUIT Caryopsis with adherent pericarp; linear; dark brown.

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.