Plants perennial; usually cespitose, often with short, knotty rhizomes, occasionally with elongate rhizomes, never stoloniferous. Culms 5-180 cm, erect, mostly glabrous, lower nodes sometimes with hairs. Sheaths 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. Inflorescences terminal, usually panicles (sometimes reduced to racemes), 5-40 cm, exceeding the upper leaves, exserted. Spikelets 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. Glumes 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. Caryopses dorsiventrally compressed and reniform in cross section, dark brown; embryos about 2/5 as long as the caryopses. x = 10.


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.


Tridens, 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 Erioneuron and Dasyochloa in Tridens; Tateoka (1961) demonstrated that they should be excluded. One of the differences between Tridens and the other two genera lies in their chromosome bases numbers, 10 in Tridens and 8 in Erioneuron and Dasyochloa. Tridens albescens is exceptional within Tridens in having chromosome numbers that suggest two base numbers, 10 and 8.


1 Primary panicle branches appressed to strongly ascending; panicles 0.3-4 cm wide, dense and spikelike. > 2
2 Lateral veins of the lemmas glabrous or pubescent only at the base Tridens albescens
2 Lateral veins of the lemmas pilose to well above the base. > 3
3 Glumes evidently longer than the adjacent lemmas, often twice as long, usually equaling or exceeding the distal florets Tridens strictus
3 Glumes from shorter than to equaling the adjacent lemmas, often exceeded by the distal florets. > 4
4 All 3 lemma veins shortly excurrent; calluses pilose Tridens carolinianus
4 Lateral lemma veins not excurrent, often terminating before the distal margin, the midvein sometimes excurrent; calluses glabrous or shortly pilose. > 5
5 Panicles 7-25 cm long, 0.3-0.8 cm wide; lemma midveins rarely excurrent Tridens muticus
5 Panicles 5-8(10) cm long, 1.2-2.5 cm wide; lemma midveins always shortly excurrent Tridens congestus
1 Primary panicle branches ascending to reflexed or drooping; panicles 1-20 cm wide, open, not spikelike. > 6
6 All pedicels shorter than 1 mm Tridens ambiguus
6 Some pedicels longer than 1 mm. > 7
7 Lateral veins of the lemmas rarely excurrent. > 8
8 Lemmas 4-6 mm; ligules 0.4-1 mm Tridens buckleyanus
8 Lemmas 2-3.2 mm; ligules 1.2-3 mm Tridens eragrostoides
7 Lateral veins of the lemmas commonly excurrent as short points. > 9
9 Blades 1-5 mm wide; panicles 5-16 cm long Tridens texanus
9 Blades mostly 3-10 mm wide; panicles 15-40 cm long Tridens flavus
... more about "Tridens"
Jesus Valdes-Reyna +
Roem. & Schult. +
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. +  and Ky. +
burbidge1953a +, gould1975c +, hitchcock1951d +  and tateoka1961a +
Gramineae +
Tridens +
Poaceae tribe Cynodonteae +