13 species are accepted. •
Tridens albescens (Vasey) Wooton & Standl. - southwest + south-central USA (
AZ NM TX LA AR OK KS), Mexico (
Chihuahua,
Durango,
Coahuila,
Tamaulipas,
Nuevo León) •
Tridens ambiguus (Elliott) Schult. – pine barren fluffgrass - southeastern USA (
TX LA MS AL GA FL SC NC) •
Tridens brasiliensis (Nees ex Steud.) Parodi -
Brazil,
Paraguay,
Uruguay,
Argentina •
Tridens carolinianus (Steud.) Henrard - southeastern USA (
LA MS AL GA FL SC NC) •
Tridens chapmanii – south-central and southeastern United States to New Jersey •
Tridens congestus (L.H.Dewey) Nash – pink fluffgrass USA (
AZ TX) •
Tridens flaccidus (Döll) Parodi -
Brazil,
Guyana,
Venezuela,
Colombia •
Tridens flavus (L.) Hitchc. – purpletop -
Ontario, eastern + central USA,
Nuevo León •
Tridens hackelii (Arechav.) Parodi -
Brazil,
Uruguay,
Argentina •
Tridens nicorae Anton - northern
Argentina •
Tridens × oklahomensis (Feath.) Feath. -
Oklahoma (hybrid
T. flavus × T. strictus) •
Tridens riograndensis Acedo & Llamas -
Rio Grande do Sul in
Brazil •
Tridens strictus (Nutt.) Nash – longspike tridens - southeastern + south-central USA (from
TX to
FL to
IL +
PA) •
Tridens texanus (S. Watson) Nash - USA (
TX NM), Mexico (
Chihuahua,
Durango,
Coahuila,
Nuevo León,
Tamaulipas,
San Luis Potosí) ; Formerly included ==References==