GrassBase - The Online World Grass Flora


W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Muhlenbergia pectinata

HABIT Annual. Culms decumbent; 10–33 cm long; 0.3–0.5 mm diam.; without nodal roots, or rooting from lower nodes. Culm-internodes 1–38 cm long. Lateral branches ample; arising from lower culm and mid culm. Leaf-sheaths 1.2–4 cm long; longer than adjacent culm internode; glabrous on surface; outer margin hairy. Ligule a ciliate membrane; 0.3–0.4 mm long. Leaf-blades flat, or involute; 1–6 cm long; 0.6–2 mm wide. Leaf-blade surface pubescent, or pilose.

INFLORESCENCE Inflorescence a panicle; exserted, or embraced at base by subtending leaf.

Panicle open, or contracted; oblong; 4–12 cm long; 0.5–2.6 cm wide. Primary panicle branches appressed, or ascending; 1 -nate; 2–3.5 cm long.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 1–3 mm long; smooth.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 3–4.5 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus pubescent.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; 0.8–1.7 mm long; 0.8 length of upper glume; membranous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute, or acuminate; muticous, or mucronate, or awned; 1 -awned. Lower glume awn 0–1.5 mm long. Upper glume lanceolate; 1–2 mm long; 0.33–0.5 length of adjacent fertile lemma; membranous; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume apex acute, or acuminate; muticous, or mucronate, or awned; 1 -awned. Upper glume awn 0–1.5 mm long.

FLORETS Fertile lemma linear, or lanceolate; 3–4.5 mm long; membranous; without keel; 3 -veined. Lemma lateral veins prominent. Lemma surface smooth, or scaberulous; rough in lines. Lemma margins eciliate, or ciliate; hairy above. Lemma apex acuminate; awned; 1 -awned. Principal lemma awn flexuous; 10–32 mm long overall. Palea 2.4–4.4 mm long; 2 -veined. Palea surface glabrous.

FLOWER Lodicules 2; cuneate; fleshy. Anthers 3; 0.3–0.6 mm long.

FRUIT Caryopsis with adherent pericarp; fusiform; 0.6–3.1 mm long; light brown.

DISTRIBUTION North America: southwest USA and Mexico.

NOTES Eragrostideae. Peterson 1994.

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