1. Family: Poaceae Barnhart
    1. Genus: Elymus L.
      1. Elymus riparius Wiegand

        This species is accepted, and its native range is SE. Canada, N. Central & E. U.S.A. to NE. Mexico.

    [GB]
    Habit
    Perennial; caespitose. Rhizomes absent. Culms slender; 100-150 cm long. Leaf-sheaths glabrous on surface. Ligule an eciliate membrane. Leaf-blades 5-15 mm wide. Leaf-blade surface scabrous.
    Inflorescences
    Inflorescence composed of racemes. Racemes 1; single; drooping; bilateral; 7-20 cm long. Rhachis flattened. Spikelet packing broadside to rhachis. Rhachis internodes oblong. Spikelets in pairs. Fertile spikelets sessile; 2 in the cluster.
    Spikelets
    Spikelets comprising 2-3 fertile florets; with diminished florets at the apex. Spikelets elliptic to oblong; laterally compressed; 10-12 mm long; breaking up at maturity; disarticulating below each fertile floret.
    Fertile
    Spikelets comprising 2-3 fertile florets; with diminished florets at the apex. Spikelets elliptic to oblong; laterally compressed; 10-12 mm long; breaking up at maturity; disarticulating below each fertile floret.
    Glume
    Glumes persistent; similar; reaching apex of florets. Lower glume lanceolate; 10 mm long; 1 length of upper glume; coriaceous; without keels; 2-4 -veined. Lower glume apex attenuate; awned; 1 -awned. Lower glume awn 10-15 mm long. Upper glume lanceolate; 10 mm long; coriaceous; without keels; 2-4 -veined. Upper glume lateral veins ribbed. Upper glume apex attenuate; awned; 1 -awned. Upper glume awn 10-15 mm long.
    Florets
    Fertile lemma lanceolate; 10-12 mm long; coriaceous; without keel; 5 -veined. Lemma surface smooth, or scaberulous. Lemma apex attenuate; awned; 1 -awned. Principal lemma awn straight; subterete below; 20-30 mm long overall. Palea 0.7-0.9 length of lemma; 2 -veined. Apical sterile florets resembling fertile though underdeveloped.
    Flowers
    Lodicules 2; membranous. Anthers 3. Stigmas 2.
    Fruits
    Hilum linear.
    Distribution
    North America: eastern Canada, northwest USA, north-central USA, northeast USA, southwest USA, southeast USA, and Mexico.
    Reference
    Triticeae. Man US Grasses 2000.

    Distribution

    Native to:

    Arkansas, Connecticut, Delaware, District of Columbia, Florida, Georgia, Illinois, Indiana, Iowa, Kentucky, Maine, Maryland, Masachusettes, Mexico Northeast, Minnesota, Mississippi, Missouri, New Hampshire, New Jersey, New York, North Carolina, Ohio, Ontario, Pennsylvania, Québec, Rhode I., South Carolina, Tennessee, Vermont, Virginia, West Virginia, Wisconsin

    Elymus riparius Wiegand appears in other Kew resources:

    First published in Rhodora 20: 84 (1918)

    Accepted by

    • Flora of North America Editorial Committee (2007). Flora of North America North of Mexico 24: 1-908. Oxford University Press, New York, Oxford.
    • Clayton, W.D., Harman, K.T. & Williamson, H. (2006). World Grass Species - Synonymy database The Board of Trustees of the Royal Botanic Gardens, Kew.
    • Dávila, P., Mejia-Saulés, M.T., Gómez-Sánchez, N., Valdés-Reyna, J., Ortíz, J.J., Morín, C., Castrejón, J. & Ocampo, A. (2006). Catálogo de las Gramíneas de México: 1-671. CONABIO, México city.

    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.
    • Dávila, P., Mejia-Saulés, M.T., Gómez-Sánchez, N., Valdés-Reyna, J., Ortíz, J.J., Morín, C., Castrejón, J. & Ocampo, A. (2006). Catálogo de las Gramíneas de México: 1-671. CONABIO, México city.

    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 2020. 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 2020. 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