TaxonIllustrator 
FNA25 P09 Tridens pg 35.jpegTridens albescens
Tridens strictus
Tridens carolinianus
Karen Klitz
Linda A. Vorobik
Karen Klitz
Linda A. Vorobik
Karen Klitz
Linda A. Vorobik
FNA25 P10 Tridens pg 37.jpegTridens muticus
Tridens muticus var. elongatus
Tridens muticus var. muticus
Tridens congestus
Karen Klitz
Linda A. Vorobik
Karen Klitz
Linda A. Vorobik
Karen Klitz
Linda A. Vorobik
Karen Klitz
Linda A. Vorobik
FNA25 P11 Tridens pg 38.jpegTridens ambiguus
Tridens buckleyanus
Tridens eragrostoides
Karen Klitz
Linda A. Vorobik
Karen Klitz
Linda A. Vorobik
Karen Klitz
Linda A. Vorobik
... further results

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; upper glumes shorter than or about equal to the lower 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.

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

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.

Key

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 Tridenscongestus
1 Primary panicle branches ascending to reflexed or drooping; panicles 1-20 cm wide, open, not spikelike. > 2
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. > 8
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

"decumbent" is not a number.

... more about "Tridens"
rounded to truncate +
emarginate to bilobed +
Jesus Valdes-Reyna +
Roem. & Schult. +
1 (?) +  and 3 (?) +
multiple +, , +  and single +
keeled +  and rounded +
pseudopetiolate +  and branching +
not fused +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
membranous +
not pseudopetiolate +
6 cm60 mm <br />0.06 m <br /> (25 cm250 mm <br />0.25 m <br />) +
pubescent +  and glabrous +
involute +  and flat +
0.1 cm1 mm <br />0.001 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
spikelike +
pilose +  and glabrous +
reniform +  and compressed +
triangular +  and dome--shaped +
sometimes longer +
membranous +
5 cm50 mm <br />0.05 m <br /> (180 cm1,800 mm <br />1.8 m <br />) +
not woody +
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. +
not waisted +
capillary +
pistillate +  and staminate +
sometimes longer +
4 +  and 11 +
sterile +  and bisexual +
round +  and compressed +
reduced +
shorter or longer +
subtending +
uncinate +
paniculate +  and racemose +
5 cm50 mm <br />0.05 m <br /> (40 cm400 mm <br />0.4 m <br />) +
hollow +  and solid +
not absent +
membranous +
sometimes longer +
membranous +
adnate +  and free +
inconspicuous +
not thick +
0 cm0 mm <br />0 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
concealed +  and prominent +
2 +  and 1 +
pubescent +  and glabrous +
dry +  and fleshy +
spikelike +
burbidge1953a +, gould1975c +, hitchcock1951d +  and tateoka1961a +
stoloniferous +
elongate +  and knotty +
1 +  and 60 +
compressed +
0.4 cm4 mm <br />0.004 m <br /> (1 cm10 mm <br />0.01 m <br />) +
1 +  and 3 +
compound +  and simple +
2 (?) +  and 3 (?) +
Gramineae +
Tridens +
Poaceae tribe Cynodonteae +
membranous +
ciliolate +, glabrous +  and hairy +
7 (?) +  and 13 (?) +
plant +  and cespitose +
aquatic +  and terrestrial +
dioecious +, monoecious +  and synoecious +