1. Family: Poaceae Barnhart
    1. Leymus Hochst.

      1. This genus is accepted, and its native range is Subarctic & Temp. Northern Hemisphere to N. Mexico, S. South America.

    [GB]

    nonem

    Habit
    Perennial. Rhizomes absent (13), or short (12), or elongated (26). Culms erect (28/31), or geniculately ascending (8/31), or decumbent (1/31); robust (2/2); 10-69.4-350 cm long. Culm-internodes terete (1/1). Culm-nodes constricted (1/1). Lateral branches sparse (2/3), or fastigiate (1/3). Leaf-sheath auricles absent (41), or falcate (11). Ligule an eciliate membrane (48), or a ciliolate membrane (2). Leaf-blades filiform (1), or linear (49); herbaceous (14), or coriaceous (36); stiff (47), or firm (3). Leaf-blade apex muticous (48), or pungent (2).
    Inflorescences
    Inflorescence composed of racemes; exserted (49), or embraced at base by subtending leaf (1). Racemes single; erect (19), or ascending (30), or drooping (2); linear (48), or oblong (5); bilateral. Rhachis flattened (25/25). Spikelet packing broadside to rhachis; crowded (11), or contiguous (31), or lax (7), or distant (1); 2 -rowed (2/2). Rhachis internodes indefinite (24), or filiform (1), or linear (24), or oblong (1). Spikelets appressed (18/18); solitary (13), or in pairs (37), or in threes (19), or clustered at each node (6). Fertile spikelets sessile (45), or sessile and pedicelled (4), or pedicelled (3); 1 in the cluster (6/42), or 2 in the cluster (38/42), or 3 in the cluster (21/42), or 4 in the cluster (8/42), or 5 in the cluster (6/42), or 6 in the cluster (3/42), or 7-11 in the cluster (1/42).
    Spikelets
    Spikelets comprising 1-5-12 fertile florets; with diminished florets at the apex. Spikelets lanceolate (2), or elliptic (22), or oblong (27), or cuneate (1); laterally compressed; 6-14.91-32 mm long; breaking up at maturity; disarticulating below each fertile floret. Spikelet callus glabrous (2/4), or pilose (2/4); base truncate (2/2). Rhachilla internodes glabrous (35), or sparsely hairy (1), or pubescent (13), or pilose (1). Floret callus glabrous (2/7), or sparsely hairy (1/7), or pubescent (3/7), or pilose (2/7).
    Fertile
    Spikelets comprising 1-5-12 fertile florets; with diminished florets at the apex. Spikelets lanceolate (2), or elliptic (22), or oblong (27), or cuneate (1); laterally compressed; 6-14.91-32 mm long; breaking up at maturity; disarticulating below each fertile floret. Spikelet callus glabrous (2/4), or pilose (2/4); base truncate (2/2). Rhachilla internodes glabrous (35), or sparsely hairy (1), or pubescent (13), or pilose (1). Floret callus glabrous (2/7), or sparsely hairy (1/7), or pubescent (3/7), or pilose (2/7).
    Glume
    Glumes distichous (36), or collateral (14); persistent; shorter than spikelet (45/48), or reaching apex of florets (8/48), or exceeding apex of florets (3/48). Lower glume subulate (24), or linear (10), or lanceolate (20), or oblong (1); 0.5-0.9711-1 length of upper glume; chartaceous (2/36), or herbaceous (1/36), or coriaceous (33/36); without keels (1/11), or 1-keeled (10/11); 0 -veined (3/47), or 1 -veined (35/47), or 2 -veined (6/47), or 3 -veined (16/47), or 4-5 -veined (4/47), or 6-7 -veined (1/47). Lower glume lateral veins absent (27), or obscure (11), or distinct (17). Lower glume surface smooth (38), or asperulous (1), or scabrous (15); glabrous (43), or pubescent (7), or pilose (1), or villous (1). Lower glume apex acuminate (7/21), or attenuate (7/21), or setaceously attenuate (9/21); muticous (23/27), or awned (4/27). Upper glume subulate (24), or linear (10), or lanceolate (20), or oblong (1); 0.25-1.031-2 length of adjacent fertile lemma; chartaceous (2/36), or herbaceous (1/36), or coriaceous (33/36); with undifferentiated margins (42), or membranous margins (8); without keels (5/15), or 1-keeled (10/15); 0 -veined (2/47), or 1 -veined (36/47), or 2 -veined (6/47), or 3 -veined (15/47), or 4-5 -veined (4/47), or 6-7 -veined (1/47). Upper glume surface smooth (38), or scabrous (14); glabrous (43), or pubescent (7), or villous (1). Upper glume apex acuminate (6/21), or attenuate (7/21), or setaceously attenuate (9/21); muticous (23/27), or awned (4/27); 1 -awned (4/4).
    Florets
    Fertile lemma lanceolate (46), or elliptic (6), or oblong (4), or ovate (1); membranous (1), or chartaceous (10), or coriaceous (40); of similar consistency on margins (48), or much thinner on margins (2); without keel (39/47), or keeled (8/47); 5 -veined (45), or 6 -veined (7), or 7 -veined (12), or 8-9 -veined (2), or 10 -veined (1). Lemma lateral veins obscure (12/16), or distinct (2/16), or prominent (2/16); without ribs (49), or ribbed (1). Lemma surface smooth (45), or asperulous (2), or scaberulous (3), or scabrous (4); glabrous (27), or puberulous (7), or pubescent (13), or pilose (6), or villous (3). Lemma margins eciliate (40), or ciliate (7), or pubescent (4). Lemma apex entire (48), or dentate (2); 2 -fid (2/2); acute (22/46), or acuminate (23/46), or attenuate (2/46), or setaceously attenuate (1/46); muticous (21), or mucronate (9), or awned (32); 1 -awned (32/32). Principal lemma awn apical (36/37), or from a sinus (1/37). Palea 0.9-0.9882-1 length of lemma; 2 -veined (48/48). Palea keels smooth (43), or scaberulous (4), or scabrous (3); eciliate (30), or ciliolate (7), or ciliate (15). Palea surface glabrous (46), or pubescent (2), or pilose (2). Palea apex entire (1/4), or dentate (4/4). Apical sterile florets resembling fertile though underdeveloped.
    Flowers
    Lodicules 2 (13/13); membranous (13/13). Anthers 3 (30/30). Stigmas 2 (15/15). Ovary pubescent on apex (20/20).
    Fruits
    Caryopsis with adherent pericarp (23/23); fusiform (1/2), or ellipsoid (1/2); isodiametric (1/1); smooth (1/1); apex unappendaged (2/2). Embryo 0.2 length of caryopsis. Hilum linear (14/14); 0.9 length of caryopsis.
    Distribution
    Europe (7), or Temperate Asia (39), or Tropical Asia (1), or Australasia (3), or North America (11), or South America (2), or Antarctica (1).

    Images

    Distribution

    Native to:

    Afghanistan, Alaska, Alberta, Aleutian Is., Altay, Amur, Argentina Northwest, Argentina South, Arizona, Belarus, Belgium, British Columbia, Bulgaria, Buryatiya, California, Central European Rus, Chile Central, China North-Central, China South-Central, China Southeast, Chita, Colorado, Denmark, East European Russia, Finland, France, Føroyar, Germany, Great Britain, Greece, Greenland, Iceland, Idaho, Illinois, Inner Mongolia, Iran, Ireland, Irkutsk, Japan, Kamchatka, Kazakhstan, Khabarovsk, Kirgizstan, Korea, Krasnoyarsk, Krym, Kuril Is., Labrador, Magadan, Maine, Manchuria, Manitoba, Masachusettes, Mexico Northeast, Mexico Northwest, Michigan, Minnesota, Mongolia, Montana, Nebraska, Nepal, Netherlands, Nevada, New Brunswick, New Hampshire, New Mexico, Newfoundland, North Caucasus, North European Russi, Northwest European R, Northwest Territorie, Norway, Nova Scotia, Nunavut, Ontario, Oregon, Pakistan, Pennsylvania, Primorye, Prince Edward I., Qinghai, Québec, Romania, Sakhalin, Saskatchewan, South Dakota, South European Russi, Spain, Sweden, Tadzhikistan, Texas, Tibet, Transcaucasus, Turkey, Turkey-in-Europe, Turkmenistan, Tuva, Ukraine, Utah, Uzbekistan, Washington, West Himalaya, West Siberia, Wisconsin, Wyoming, Xinjiang, Yakutskiya, Yukon

    Introduced into:

    Austria, Baltic States, Chatham Is., Chile South, Connecticut, Czechoslovakia, Falkland Is., Hawaii, Indiana, New York, New Zealand South, Tasmania, Victoria

    Leymus Hochst. appears in other Kew resources:

    First published in Flora 31: 118 (1848)

    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 2019. 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 2019. 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