Muhlenbergia annua

HABIT Annual. Culms 8–22 cm long; 0.2–0.3 mm diam. Culm-internodes 0.3–2.5 cm long; scaberulous. Leaf-sheaths 0.2–2.5 cm long; smooth, or scaberulous. Ligule an eciliate membrane; 1.6–2.5 mm long; erose, or lacerate; acute. Leaf-blades flat, or involute; 1–6 cm long; 0.8–1.5 mm wide. Leaf-blade midrib prominent beneath. Leaf-blade surface scaberulous; rough abaxially; puberulous; hairy adaxially.

INFLORESCENCE Inflorescence a panicle.

Panicle open; oblong; 5–13 cm long; 1.4–6 cm wide. Primary panicle branches ascending; 1–2 -nate; 1–3.6 cm long.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 3–8 mm long.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 1.6–2.1 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus pubescent.

GLUMES Glumes persistent; similar; exceeding apex of florets. Lower glume lanceolate; 1.6–2.1 mm long; 1 length of upper glume; membranous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex acuminate; muticous, or mucronate. Upper glume lanceolate; 1.6–2.1 mm long; 1.2 length of adjacent fertile lemma; membranous; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume apex acuminate; muticous, or mucronate.

FLORETS Fertile lemma lanceolate; 1.4–1.7 mm long; membranous; without keel; 3 -veined. Lemma midvein pubescent; hairy below. Lemma margins pubescent; hairy below. Lemma apex acute; muticous. Palea 1 length of lemma; 2 -veined. Palea surface pubescent; hairy below.

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

FRUIT Caryopsis with adherent pericarp; fusiform; 0.9–1.1 mm long.

DISTRIBUTION North America: Mexico.

NOTES Eragrostideae. Peterson 1994.

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