Psilostrophe gnaphalodes
Psilostrophe gnaphalodes is a species of flowering plant in the family Asteraceae. It is native to Texas and northern Mexico. It belongs to Psilostrophe, a genus commonly known as the paperflowers.
Description
Psilostrophe gnaphalodes is a gray to gray-green, hairy herb with yellow to orange flower heads grouped in compact, flat-topped arrays. As in other members of the genus, its leaves are arranged alternately and are usually entire, while the ray florets remain attached as the fruits mature.
The species can be distinguished from closely related paperflowers by its densely hairy cypselae. Its pappus consists of four to eight scales with torn or fringed margins; in most other species of the genus the fruits are hairless and the pappus scales have entire margins.
Taxonomy
The species was described by Swiss botanist Augustin Pyramus de Candolle in 1838 in the seventh volume of Prodromus Systematis Naturalis Regni Vegetabilis. It is the type species of the genus Psilostrophe.
A 1988 population study treated Psilostrophe mexicana, which had been described as a separate species from Mexico, as a geographically distinct variety of P. gnaphalodes. Plants of the World Online recognizes two varieties:
- Psilostrophe gnaphalodes var. gnaphalodes
- Psilostrophe gnaphalodes var. mexicana (R.C.Br.) B.L.Turner
Distribution and ecology
The species occurs from Texas south into northern Mexico. Plants of the World Online records it from Texas and the northeastern and northwestern regions of Mexico. The genus is characteristic of dry habitats in the southwestern United States and adjacent Mexico, where some species grow along roadsides.
Psilostrophe gnaphalodes has been reported as poisonous to livestock, including sheep and cattle. A model-based assessment published through Plants of the World Online predicted that the species was not threatened with extinction, with the prediction rated as confident.