1. Family: Poaceae Barnhart
    1. Genus: Stipa L.
      1. Stipa occidentalis Thurb. ex S.Watson

        This species is accepted, and its native range is W. Canada to W. U.S.A.

    [GB]
    Habit
    Perennial; caespitose; clumped densely. Culms 80-120 cm long. Culm-internodes distally glabrous, or pubescent. Leaf-sheaths glabrous on surface to pubescent. Ligule an eciliate membrane; 0.5-1 mm long; entire, or erose; truncate. Leaf-blades filiform, or linear; flat, or involute; 10-20 cm long; 1-5 mm wide. Leaf-blade surface glabrous, or puberulous.
    Inflorescences
    Inflorescence a panicle. Panicle open; linear; 5-30 cm long. Spikelets solitary. Fertile spikelets pedicelled.
    Spikelets
    Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; subterete; 7-15 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus elongated; curved; 1-1.5 mm long; pubescent; acute.
    Fertile
    Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; subterete; 7-15 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus elongated; curved; 1-1.5 mm long; pubescent; acute.
    Glume
    Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 1 length of upper glume; membranous; without keels; 3-5 -veined. Lower glume apex acuminate. Upper glume lanceolate; 7-15 mm long; hyaline; without keels; 3-7 -veined. Upper glume apex acuminate.
    Florets
    Fertile lemma lanceolate; subterete; 5-8 mm long; coriaceous; light brown; without keel; 5 -veined. Lemma surface pubescent; with conspicuous apical hairs. Lemma margins convolute; covering most of palea. Lemma hairs 0.5-1.5 mm long. Lemma apex acute; awned; 1 -awned. Principal lemma awn bigeniculate; 15-50 mm long overall; with twisted column. Middle segment of lemma awn glabrous, or hirtellous. Column of lemma awn glabrous, or hirtellous; with 1 mm long hairs. Palea 2-3.5 mm long; 0.33-0.5 length of lemma; 2 -veined; without keels. Palea surface pubescent.
    Flowers
    Lodicules 3; 1.5 mm long. Anthers 3; 2.5 mm long. Stigmas 2. Ovary glabrous.
    Fruits
    Caryopsis with adherent pericarp. Hilum linear.
    Distribution
    North America: Subarctic, western Canada, northwest USA, north-central USA, southwest USA, and south-central USA.
    Reference
    Stipeae. Fl Pac NW 1994.

    Distribution

    Native to:

    Alberta, Arizona, British Columbia, California, Colorado, Idaho, Montana, Nevada, Oregon, Utah, Washington, Wyoming

    Stipa occidentalis Thurb. ex S.Watson appears in other Kew resources:

    First published in Botany [Fortieth Parallel]: 380 (1871)

    Accepted by

    • Clayton, W.D., Harman, K.T. & Williamson, H. (2006). World Grass Species - Synonymy database The Board of Trustees of the Royal Botanic Gardens, Kew.

    Literature

    Kew Backbone Distributions
    • Flora of North America Editorial Committee (2007). Flora of North America North of Mexico 24: 1-908. Oxford University Press, New York, Oxford.

    Sources

    GrassBase - The Online World Grass Flora
    http://creativecommons.org/licenses/by-nc-sa/3.0

    Kew Backbone Distributions
    The International Plant Names Index and World Checklist of Selected Plant Families 2018. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

    Kew Names and Taxonomic Backbone
    The International Plant Names Index and World Checklist of Selected Plant Families 2018. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0