1. Family: Poaceae Barnhart
    1. Tridens Roem. & Schult.

      1. This genus is accepted, and its native range is U.S.A. to NE. Mexico, S. Tropical America.

    [GB]

    nonem

    Habit
    Perennial. Rhizomes absent (12), or short (3), or elongated (2). Culms erect (11/11); robust (1/1); 20-75.73-180 cm long. Lateral branches lacking (2/2). Ligule an eciliate membrane (1), or a ciliate membrane (4), or a fringe of hairs (12).
    Inflorescences
    Inflorescence a panicle, or composed of racemes (1); terminal (16), or terminal and axillary (1). Panicle open (10), or contracted (6), or spiciform (1). Racemes borne along a central axis (1/1). Spikelets appressed (2/2), or ascending (1/2); solitary. Fertile spikelets pedicelled.
    Spikelets
    Spikelets comprising 3-7-15 fertile florets; with diminished florets at the apex. Spikelets elliptic (1), or oblong (13), or ovate (2), or orbicular (1), or cuneate (1); laterally compressed; 3-7.391-15 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus glabrous (1/11), or pubescent (10/11).
    Fertile
    Spikelets comprising 3-7-15 fertile florets; with diminished florets at the apex. Spikelets elliptic (1), or oblong (13), or ovate (2), or orbicular (1), or cuneate (1); laterally compressed; 3-7.391-15 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus glabrous (1/11), or pubescent (10/11).
    Glume
    Glumes persistent; shorter than spikelet (16), or reaching apex of florets (1); thinner than fertile lemma (8), or similar to fertile lemma in texture (9). Lower glume lanceolate (6), or oblong (8), or ovate (3); 0.25-0.8888-1.2 length of upper glume; membranous; 1-keeled; 1 -veined, or 2-7 -veined (1). Lower glume lateral veins absent (16), or distinct (1). Lower glume apex emarginate (2), or obtuse (6), or acute (14), or acuminate (3); muticous (7), or mucronate (10). Upper glume lanceolate (6), or oblong (8), or ovate (3); 0.5-1.026-2 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined, or 2-7 -veined (1). Upper glume apex emarginate (1), or obtuse (7), or acute (13), or acuminate (3); muticous (14), or mucronate (3).
    Florets
    Fertile lemma lanceolate (3), or elliptic (11), or oblong (2), or ovate (2); membranous (9), or chartaceous (8); without keel; 3 -veined. Lemma midvein eciliate (1), or ciliate (4), or pubescent (12). Lemma lateral veins obscure (1/1); excurrent (13), or extending close to apex (6). Lemma margins eciliate (1), or ciliate (6), or pubescent (10). Lemma apex entire (5), or dentate (14); 2 -fid (13/14), or 3 -fid (1/14); emarginate (5/6), or obtuse (5/6); muticous (2), or mucronate (14), or awned (2); 1 -awned (1/2), or 3 -awned (1/2). Principal lemma awn apical (15/16), or from a sinus (1/16). Palea 0.6-0.8617-1 length of lemma; 2 -veined (1/1). Palea keels smooth (14), or scaberulous (1), or scabrous (2), or tuberculate (1); eciliate (15), or pubescent (1), or ciliolate (1). Palea surface glabrous (16), or pubescent (1). Palea apex dentate (2/2). Apical sterile florets resembling fertile though underdeveloped.
    Flowers
    Lodicules 2 (1/1); fleshy (1/1). Anthers 3 (5/5).
    Fruits
    Caryopsis with adherent pericarp; lanceolate (1/12), or ellipsoid (4/12), or oblong (6/12), or ovoid (1/12), or obovoid (1/12); dorsally compressed (4/4); plano-convex (1/2), or concavo-convex (1/2); reticulate (2/2). Embryo 0.4-0.425-0.5 length of caryopsis. Hilum punctiform (4/5), or elliptic (1/5).
    Distribution
    Africa (1), or North America (11), or South America (6).

    Images

    Distribution

    Native to:

    Alabama, Argentina Northeast, Argentina Northwest, Arizona, Arkansas, Brazil North, Brazil Northeast, Brazil South, Brazil Southeast, Brazil West-Central, Colombia, Connecticut, Delaware, District of Columbia, Florida, Georgia, Guyana, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Masachusettes, Mexico Northeast, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Ohio, Oklahoma, Paraguay, Pennsylvania, Rhode I., South Carolina, Tennessee, Texas, Uruguay, Venezuela, Vermont, Virginia, West Virginia, Wisconsin

    Introduced into:

    California, Ontario

    Tridens Roem. & Schult. appears in other Kew resources:

    First published in Syst. Veg., ed. 15 bis 2: 34 (1817)

    Accepted by

    • Govaerts, R. (2019). World Checklist of Vascular Plants (WCVP Database) The Board of Trustees of the Royal Botanic Gardens, Kew.

    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