GrassBase - The Online World Grass Flora

Descriptions

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

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

Anthoxanthum occidentale

HABIT Perennial; caespitose. Rhizomes elongated. Culms 60–90 cm long. Leaf-sheaths scaberulous. Ligule an eciliate membrane; 3–6 mm long; pubescent on abaxial surface; erose; obtuse, or acute. Leaf-blades 20–40 cm long; 7–12 mm wide; aromatic. Leaf-blade venation prominent; with distinct cross veins. Leaf-blade margins scabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle open; ovate; 8–13 cm long; bearing few spikelets. Primary panicle branches drooping.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 2 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; laterally compressed; 5 mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma; shiny. Lower glume ovate; 4 mm long; 1 length of upper glume; membranous; 1-keeled; 3 -veined. Lower glume apex acute. Upper glume ovate; 4 mm long; membranous; 1-keeled; 3 -veined. Upper glume apex acute.

FLORETS Basal sterile florets similar; male; with palea; attached to and deciduous with the fertile. Lemma of lower sterile floret elliptic; 4.5 mm long; 0.9 length of fertile lemma; chartaceous; 1-keeled; 5 -veined; puberulous; ciliate on margins; dentate; 2 -fid; obtuse; muticous, or mucronate. Lemma of upper sterile floret oblong; 1 length of lower sterile floret; chartaceous; pubescent; ciliate on margins; lobed; 2 -fid; obtuse; muticous, or mucronate. Fertile lemma ovate; 4.5 mm long; cartilaginous; shiny; without keel. Lemma surface puberulous; hairy above. Lemma margins convolute; covering most of palea. Lemma apex acute. Palea elliptic; 1 -veined; without keels.

FLOWER Anthers 2 (bisexual), or 3 (male); 2.5 mm long. Stigmas plumose. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION North America: northwest USA and southwest USA.

NOTES Aveneae. Fl Pac SW 1994.

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