View source for Tridens

{{Treatment/ID
|accepted_name=Tridens
|accepted_authority=Roem. & Schult.
|publications=
|basionyms=
|synonyms=
|hierarchy=Poaceae;Poaceae subfam. Chloridoideae;Poaceae tribe Cynodonteae;Tridens
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Poaceae]]</div><div class="higher-taxon"><small>subfamily</small>[[Poaceae subfam. Chloridoideae]]</div><div class="higher-taxon"><small>tribe</small>[[Poaceae tribe Cynodonteae]]</div><div class="higher-taxon"><small>genus</small>[[Tridens]]</div></div>
|volume=Volume 25
|mention_page=
|treatment_page=page 33
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Plants </b>perennial; usually cespitose, often with short, knotty rhizomes, occasionally with elongate rhizomes, never stoloniferous. <b>Culms</b> 5-180 cm, erect, mostly glabrous, lower nodes sometimes with hairs. <b>Sheaths</b> shorter than the internodes, open; ligules membranous and ciliate or of hairs; blades 6-25 cm long, 1-8 mm wide, flat or involute, margins not thick and cartilaginous. <b>Inflorescences</b> terminal, usually panicles (sometimes reduced to racemes), 5-40 cm, exceeding the upper leaves, exserted. <b>Spikelets</b> 4-10(13) mm, laterally compressed, with 4-11(16) florets, more than 1 floret bisexual; sterile florets distal to the fertile spikelets; disarticulation above the glumes. <b>Glumes</b> from shorter than to equaling the distal florets; lower glumes 1(3)-veined; lower glumes shorter than or about equal to the upper glumes, 1-3(9)-veined, unawned; calluses usually glabrous, sometimes pilose; lemmas hyaline or membranous, 3-veined, veins usually shortly hairy below, apices rounded to truncate, emarginate to bilobed, midvein often excurrent to 0.5 mm, lateral veins not or more shortly excurrent; paleas glabrous or shortly pubescent on the lower back and margins, veins glabrous or ciliolate; lodicules 2, free or adnate to the palea; anthers 3, reddish-purple. <b>Caryopses</b> dorsiventrally compressed and reniform in cross section, dark brown; embryos about 2/5 as long as the caryopses. <b>x</b> = 10.</span><!--

-->{{Treatment/Body
|distribution=Conn.;N.J.;N.Y.;D.C;Del.;Ill.;Ind.;Kans.;Mich.;Minn.;Nebr.;N.Mex.;Nev.;Ohio;Okla.;Wis.;W.Va.;Ont.;Fla.;N.H.;Ariz.;Tex.;La.;N.C.;Tenn.;S.C.;Pa.;Ala.;Calif.;Va.;Colo.;Md.;Mass.;R.I.;Vt.;Ark.;Ga.;Iowa;Utah;Mo.;Miss.;Ky.
|discussion=<p><i>Tridens</i>, a genus of 14 species, is native to the Americas; all ten species described here are native to the the Flora region. Hitchcock (1951) included both <i>Erioneuron</i> and <i>Dasyochloa</i> in <i>Tridens</i>; Tateoka (1961) demonstrated that they should be excluded. One of the differences between <i>Tridens</i> and the other two genera lies in their chromosome bases numbers, 10 in <i>Tridens</i> and 8 in <i>Erioneuron</i> and <i>Dasyochloa</i>. <i>Tridens albescens</i> is exceptional within <i>Tridens</i> in having chromosome numbers that suggest two base numbers, 10 and 8.</p>
|tables=
|references={{Treatment/Reference
|id=burbidge1953a
|text=Burbidge, N.T. 1953. The genus Triodia R. Br. (Gramineae). Austral. J. Bot. 1:121-184
}}{{Treatment/Reference
|id=gould1975c
|text=Gould, F.W. 1975. The grasses of Texas. Texas A&M University Press, College Station, Texas, U.S.A. 653 pp.
}}{{Treatment/Reference
|id=hitchcock1951d
|text=Hitchcock, A.S. 1951 [title page 1950]. Manual of the Grasses of the United States, ed. 2, rev. A. Chase. U.S.D.A. Miscellaneous Publication No. 200. U.S. Government Printing Office, Washington, D.C., U.S.A. 1051 pp.
}}{{Treatment/Reference
|id=tateoka1961a
|text=Tateoka, T. 1961. A biosystematic study of Tridens (Gramineae). Amer. J. Bot. 48:565-573.
}}
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|- id="key-0-1"
|1
|Primary panicle branches appressed to strongly ascending; panicles 0.3-4 cm wide, dense and spikelike.
|[[#key-0-2| > 2]]
|- id="key-0-2"
|2
|Lateral veins of the lemmas glabrous or pubescent only at the base
|[[Tridens albescens|Tridens albescens]]
|- id="key-0-2"
|2
|Lateral veins of the lemmas pilose to well above the base.
|[[#key-0-3| > 3]]
|- id="key-0-3"
|3
|Glumes evidently longer than the adjacent lemmas, often twice as long, usually equaling or exceeding the distal florets
|[[Tridens strictus|Tridens strictus]]
|- id="key-0-3"
|3
|Glumes from shorter than to equaling the adjacent lemmas, often exceeded by the distal florets.
|[[#key-0-4| > 4]]
|- id="key-0-4"
|4
|All 3 lemma veins shortly excurrent; calluses pilose
|[[Tridens carolinianus|Tridens carolinianus]]
|- id="key-0-4"
|4
|Lateral lemma veins not excurrent, often terminating before the distal margin, the midvein sometimes excurrent; calluses glabrous or shortly pilose.
|[[#key-0-5| > 5]]
|- id="key-0-5"
|5
|Panicles 7-25 cm long, 0.3-0.8 cm wide; lemma midveins rarely excurrent
|[[Tridens muticus|Tridens muticus]]
|- id="key-0-5"
|5
|Panicles 5-8(10) cm long, 1.2-2.5 cm wide; lemma midveins always shortly excurrent
|[[Tridens congestus]]
|- id="key-0-1"
|1
|Primary panicle branches ascending to reflexed or drooping; panicles 1-20 cm wide, open, not spikelike.
|[[#key-0-2| > 2]]
|- id="key-0-6"
|6
|All pedicels shorter than 1 mm
|[[Tridens ambiguus|Tridens ambiguus]]
|- id="key-0-6"
|6
|Some pedicels longer than 1 mm.
|[[#key-0-7| > 7]]
|- id="key-0-7"
|7
|Lateral veins of the lemmas rarely excurrent.
|[[#key-0-8| > 8]]
|- id="key-0-8"
|8
|Lemmas 4-6 mm; ligules 0.4-1 mm
|[[Tridens buckleyanus|Tridens buckleyanus]]
|- id="key-0-8"
|8
|Lemmas 2-3.2 mm; ligules 1.2-3 mm
|[[Tridens eragrostoides|Tridens eragrostoides]]
|- id="key-0-7"
|7
|Lateral veins of the lemmas commonly excurrent as short points.
|[[#key-0-8| > 8]]
|- id="key-0-9"
|9
|Blades 1-5 mm wide; panicles 5-16 cm long
|[[Tridens texanus|Tridens texanus]]
|- id="key-0-9"
|9
|Blades mostly 3-10 mm wide; panicles 15-40 cm long
|[[Tridens flavus|Tridens flavus]]
|}
</div></div><!--

-->{{#Taxon:
name=Tridens
|author=Jesus Valdes-Reyna;
|authority=Roem. & Schult.
|rank=genus
|parent rank=tribe
|synonyms=
|basionyms=
|family=Poaceae
|distribution=Conn.;N.J.;N.Y.;D.C;Del.;Ill.;Ind.;Kans.;Mich.;Minn.;Nebr.;N.Mex.;Nev.;Ohio;Okla.;Wis.;W.Va.;Ont.;Fla.;N.H.;Ariz.;Tex.;La.;N.C.;Tenn.;S.C.;Pa.;Ala.;Calif.;Va.;Colo.;Md.;Mass.;R.I.;Vt.;Ark.;Ga.;Iowa;Utah;Mo.;Miss.;Ky.
|reference=burbidge1953a;gould1975c;hitchcock1951d;tateoka1961a
|publication title=
|publication year=
|special status=
|source xml=https://bitbucket.org/aafc-mbb/fna-data-curation/src/2e0870ddd59836b60bcf96646a41e87ea5a5943a/coarse_grained_fna_xml/V25/V25_47.xml
|subfamily=Poaceae subfam. Chloridoideae
|tribe=Poaceae tribe Cynodonteae
|genus=Tridens
}}<!--

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[[Category:Treatment]]
[[Category:Poaceae tribe Cynodonteae]]
[[Category:Revised Since Print]]