Thelesperma, commonly known as greenthreads, is a genus of annual or perennialherbs and subshrubs found in the Americas. Members of this genus are closely related to some species of Coreopsis and Bidens. The genus is considered to be within the family Asteraceae.
Description
Plants of this genus are annual or perennialherbs or subshrubs that typically range from 10 to 70 cm (3.9 to 27.6 in) in height. Most species of this genus have opposite leaves that contain pinnately lobed, usually glabrous leaf blades. Depending on the species, the leaves can be mostly basal to mostly cauline. The species bear radiate or discoidflower heads that are borne singly or are in loose, corymbiform arrays. Each flower head contains up to eight ray florets (some sp. do not have ray florets) with yellow, reddish brown or yellow and brown bicolored corollas, and 20 to over 100 yellow or brown disc florets.[2]
The name Thelesperma is derived from the ancient Greek words θηλή (transl. grc – transl. Thele, meaning "nipple") and σπέρμα (transl. grc – transl. sperma, meaning "seed") referring to the papillatecypselae of some of the species.[2]
In English, the genus is commonly known as greenthreads.[8]
Members of the genus are used by a number of the southwestern Native Americanpeoples as an herbal tea. T. megapotamicum contains luteolin.[9] It also appears that many of the species contain a very similar chromatographic profile, and thus may contain very similar profiles of flavenoids.[10]
^Crawford, D. J.; Mort, M. E. (2005), "Phylogeny of Eastern North American Coreopsis (Asteraceae-Coreopsideae): insights from nuclear and plastid sequences, and comments on character evolution", American Journal of Botany, 92 (2): 330–336, doi:10.3732/ajb.92.2.330, PMID21652409
^Hansen, C. J., L. Allphin, and M. D. Windham. 2002. Biosystematic analysis of the Thelesperma subnudum complex (Asteraceae). Sida 20: 71–96.
