{{Short description|Species of plant}} {{Speciesbox | image = Tridens texanus (1).jpg | image_caption = ''Tridens texanus'', drooping inflorescence. | genus = Tridens (plant) | species = texanus | authority = (S.Watson) Nash | synonyms = {{Species list |Sieglingia texana|(S.Watson) Kuntze |Triodia texana|S.Watson Tricuspis texana|Thurb. ex S.Watson }} | synonyms_ref = <ref name="kew">{{cite web | url = https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:257787-2 | title = ''Tridens texanus'' (S.Watson) Nash | date = 2026 | website = Plants of the World Online | location = United Kingdom | publisher = Royal Botanic Gardens Kew | access-date = February 6, 2026 }}</ref>}}
'''''Tridens texanus''''', often called '''Texas fluffgrass''' and '''Texas tridens''', is a species of grass belonging to the family Poaceae.<ref name="kew" />
==Description==
Species of the New World genus ''Tridens'' are similar to many other grass species developing panicle-type inflorescences. However, certain features -- often hard to see without magnification and knowledge of basic grass-flower anatomy -- help identify ''Tridens'' species:<ref name="s">{{cite book | last = Small | first = John Kunkel | title = Flora of the southeastern United States; being descriptions of the seed-plants, ferns and fern-allies growing naturally in North Carolina, South Carolina, Georgia, Florida, Tennessee, Alabama, Mississippi, Arkansas, Louisiana and the Indian territory and in Oklahoma and Texas east of the one-hundredth meridian | publisher = the author | date = 1903 | location = | pages = 141 | url = https://www.biodiversitylibrary.org/page/377028}}</ref><ref>{{cite web | url = https://www.worldfloraonline.org/taxon/wfo-4000039110 | title = Tridens Roem. & Schult. | date = 2026 | website = WFO The World Flora Online | access-date = February 7, 2026 }}</ref><ref>{{cite web | url = https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=11192 | title = ''Tridens'', in Jepson Flora Project (eds.) | last = Smith | first = James P. | date = 2012 | website = Jepson eFlora | location = California, USA | publisher = University of California | access-date = February 7, 2026 }}</ref>
*Spikelets are not compressed laterally, or sideways, but rather are plump to rounded in cross-section; they accommodate 3 or more florets. *The lemma's 3 prominent veins are hairy, at least below, while the glumes are hairless. *Neither glumes nor lemmas bear needlelike awns at their tips.
These features help distinguish ''Tridens texanus'' from other ''Tridens'' species:<ref name="s" /><ref>{{cite web | url = https://fsus.ncbg.unc.edu/main.php?pg=show-key.php&taxonid=65983 | title = Key to Tridens | last = Weakley | first = A.S. | date = 2026 | website = Flora of the Southeastern United States 2025 Edition | location = Chapel Hill, U.S.A | publisher = University of North Carolina Herbarium, North Carolina Botanical Garden | access-date = February 7, 2026 }}</ref>
*The panicle-type inflorescence is open and diffuse, not spike-like. *Of the lemma's 3 nerves, the ones on the sides vanish at the margin instead of continuing strongly to the edges. *The spikelets are relatively large, up to 10 mm long.
==Distribution==
In the USA, ''Tridens texanus'' occurs in the south-central states of New Mexico and Texas.<ref name="kew" />
In Mexico, ''Tridens texanus'' occurs in the northern states of Chihuahua, Coahuila, Nuevo León, San Luis Potosí and Tamaulipas.<ref>{{cite journal | last = Dávila | first = Patricia | last2 = Mejia-Saulés | first2 = Ma. Teresa | last3 = Soriano-Martínez | first3 = Ana María | last4 = Herrera-Arrieta | first4 = Yolanda | title = Conocimiento taxonómico de la familia Poaceae en México | journal = Botanical Sciences | volume = 96 | issue = 3 | publisher = | location = | date = July–September 2018 | language = Spanish | url = https://www.botanicalsciences.com.mx/index.php/botanicalSciences/article/view/1894/1919 | issn = 2007-4476 | doi = 10.17129/botsci.1894 | access-date = February 7, 2026| doi-access = free }}</ref>
==Habitat==
In Texas, ''Tridens texanus'' is described as inhabiting brushlands.<ref name="s" /> In the Southwestern Plains, it's reported to occur infrequently on rocky limestone soils.<ref>{{cite book | title = Grasses of the Great Plains: A Pictorial Guide | last1 = Coffey | first1 = Chuck R. | last2 = Stevens | first2 = Russell L. | publisher = The Samuel Roberts Noble Foundation Agricultural Division | date = 2012 | location = Ardmore, Oklahoma, USA | url = https://mtnativeplants.org/wp-content/uploads/2025/04/Grasses-of-The-Great-Plains.pdf | isbn = 0-9754303-0-0}}</ref> Pictures on this page show an individual encountered on a limestone hill slope in an opening of Ashe Juniper forest.<ref>{{cite web | url = https://www.inaturalist.org/observations/231676270 | title = Texas Fluffgrass ''Tridens texanus'' Research Grade | date = December 1, 2013 | website = inaturalist.org | publisher = iNaturalist | access-date = February 8, 2026 }}</ref>
In Mexico, a study of the grasses in a mesquite woodland in north-central Nuevo León state found ''Tridens texanus'' to be the fourth most frequently documented grass species, appearing in about 13% of sampled sites. More frequently occurring companion species, in descending order, were ''Cenchrus ciliaris'' (as ''Pennisetum cilare''), ''Setaria texana,'' and ''Bouteloua trifida''<ref>{{cite journal | last = Guzmán-Lucio | first = Marco Antonio | last2 = Foroughbakhch-Pournavab | first2 = Rahim | last3 = Alvarado-Vázquez | first3 = Marco Antonio | last4 = Rocha-Estrada | first4 = Alejandra | last5 = Salcedo-Martínez | first5 = Sergio Manuel | title = Gramíneas de los mesquitales en el centro-norte de Nuevo León | journal = Polibotánica | volume = 42 | pages = 19-42 | publisher = Instituto Politécnico Nacional | location = Nuevo León, México | date = 2016 | language = Spanish with English extract | url = https://www.redalyc.org/journal/621/62146619002/html/ | doi = 10.18387/polibotanica.42.2 | access-date = February 8, 2026| doi-access = free }}</ref> Also in Mexico the species has been collected at the edge of a field.<ref>{{cite book | last = Hitchcock | first = A.S. | title = Mexican Grasses in the United States National Herbarium | publisher = U.S. Government Printing Office | date = 1913 | location = Washington, DC, USA | pages = 357 | url = https://repository.si.edu/bitstream/handle/10088/26966/usnh_0017.03.pdf}}</ref>
==Taxonomy==
In 1883, when Sereno Watson first described ''Tridens texanus'' as ''Triodia texana'', he noted collections by Wright from Western Texas and New Mexico, and in Mexico at Monclova, Coahuila.<ref name="t">{{cite book | last = Watson | first = Sereno | chapter= X | title = Proceedings of the American Academy of Arts and Sciences | publisher = John Wilson and Son | volume = 18 | date = 1883 | location = Boston | pages = 180 | url = https://archive.org/details/proceedingsofame18amer/page/180/mode/2up}}</ref>
===Phylogeny===
Molecular phylogenetic analysis confirms ''Tridens texanus'' as a member of the strict concept of the genus ''Tridens'', and belonging to the subtribe Pappophorinae.<ref>{{cite journal | last = Peterson | first = Paul M. | last2 = Romaschenko | first2 = Konstantin | last3 = Herrera Arrieta | first3 = Yolanda | title = A molecular phylogeny and classification of the Cynodonteae (Poaceae: Chloridoideae) with four new genera: ''Orthacanthus, Triplasiella, Tripogonella'', and ''Zaqiqah''; three new subtribes: Dactylocteniinae, Orininae, and Zaqiqahinae; and a subgeneric classification of ''Distichlis'' | journal = Taxon | volume = 65 | issue = 6 | pages = 1263-1287 | publisher = Wiley Online Library | date = December 2016 | url = https://scispace.com/pdf/a-molecular-phylogeny-and-classification-of-the-cynodonteae-5bkwc94yyo.pdf | issn = | doi = 10.12705/656.4 | access-date = February 7, 2026}}</ref>
===Etymology===
The genus name ''Tridens'' is New Latin meaning "3-toothed," referring to the lemmas of florets of the type specimen upon which the genus was described in 1817 where, at least to the authors, the lemma's three veins appeared to gather at a notched or 2-toothed tip.<ref>{{cite web | url = https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=11192 | title = Tridens | last = Smith | first = James P. | date = 2012 | website = Jepson eFlora | location = California, USA | publisher = University of California | access-date = February 9, 2026 }}</ref> The name is constructed from the Latin and Greek ''tri-'', meaning "having 3 elements or parts."<ref>{{cite web | url = https://www.merriam-webster.com/dictionary/tri- | title = tri- combining form | website = merriam-webster.com | publisher = Merriam-Webster | access-date = February 7, 2026 }}</ref> and the Latin ''-dēns'', meaning "tooth or toothlike part.<ref>{{cite web | url = https://www.wordreference.com/definition/dens | title = dens | website = wordreference.com | publisher = WordReference.com | access-date = February 9, 2026 }}</ref>
The species name ''texanus'' refers to the US state of Texas, collections from which were examined when, in 1883, Sereno Watson described the taxon which would become ''Tridens texanus.''<ref name="t" />
==Gallery==
<gallery heights=150px mode="packed"> Tridens texanus (2).jpg| ''Tridens texanus'' spikelets shedding their mature florets Tridens texanus (3).jpg| ''Tridens texanus'' floret with hairy lower veins, and maybe a brown and maybe a brown fungal rust Tridens texanus (4).jpg| ''Tridens texanus'' ligule and hairy blade bases Tridens texanus (5).jpg| ''Tridens texanus'' in habitat </gallery>
==References== {{Reflist}}
{{Taxonbar|from=Q15510309}}
Category:Flora of Texas Category:Flora of New Mexico Category:Flora of Northeastern Mexico Category:Plants described in 1903 Category:Native grasses of Texas Category:Native grasses of the Great Plains region Category:Taxa named by George Valentine Nash Category:Chloridoideae