Thelesperma

Thelesperma is a genus of North American and South American plants in the cosmos tribe within the sunflower family. Greenthread is a common name for plants in this genus.

Members of the genus are used by a number of the southwestern Native American peoples as an herbal tea; as such, it is sometimes called "Indian tea," "Native American tea," "Native tea," or the name is referenced to the local tribe where the tea was harvested such as "Apache tea," Pueblo tea," "Navajo tea," "Hopi tea," etc. T. megapotamicum contains luteolin. It also appears that many of the species contain a very similar chromatographic profile, and thus may contain very similar profiles of flavenoids. The genus is closely related to parts of Coreopsis and to certain North American Bidens species (including Bidens coronata and Bidens comosa).

Species
As of July 2023, Plants of the World Online accepts 12 species for this genus:
 * Thelesperma burridgeanum S.F.Blake - Texas, Coahuila
 * Thelesperma filifolium (Hook.) A.Gray - United States to northeast Mexico
 * Thelesperma flavodiscum (Shinners) B.L.Turner - Texas, Louisiana, Arkansas
 * Thelesperma graminiformis (Sherff) Melchert - Nuevo León, Tamaulipas
 * Thelesperma longipes A.Gray - Arizona to Texas and northern Mexico
 * Thelesperma megapotamicum (Spreng.) Herter - United States, Mexico, Uruguay, Argentina
 * Thelesperma muelleri (Sherff) Melchert - Nuevo León, Tamaulipas
 * Thelesperma nuecense B.L.Turner - Texas
 * Thelesperma scabridulum S.F.Blake - Coahuila, Nuevo León, Tamaulipas
 * Thelesperma simplicifolium (A.Gray) A.Gray - Texas, Mexico
 * Thelesperma subaequale S.F.Blake - Coahuila, Nuevo León
 * Thelesperma subnudum A.Gray - Alberta, W. central and central United States