Psilostrophe villosa
Psilostrophe villosa is a species of flowering plant in the daisy family. Its common names include woolly paperflower and hairy paperflower. It is a small, gray-woolly plant with clusters of yellow flower heads, native to the south-central United States, where it grows in grasslands on limestone, gypsum and caliche soils.
Description
Psilostrophe villosa is a biennial or perennial herb that rarely flowers in its first year. It usually grows tall, occasionally or more. Its stems are gray to gray-green and covered in long, cobwebby hairs. As in other members of the genus, the leaves are alternate, spatula-shaped to linear, and usually untoothed.
The flower heads are borne in crowded, flat-topped clusters on short stalks, usually long. Each head has an involucre usually long and usually three yellow ray florets, sometimes two to five, with blades long that spread outward as the fruit develops. There are usually five to eight disc florets, sometimes up to twelve. In the genus, the ray corollas persist on the fruiting heads rather than falling off. The fruits are cypselae, usually hairless and sometimes gland-dotted, each topped by a pappus of four to six narrow scales or more long. The chromosome number is 2n = 32.
Taxonomy
The species was named by Per Axel Rydberg and published by Nathaniel Lord Britton in 1901, in his Manual of the Flora of the Northern States and Canada.
Psilostrophe villosa is closely related to Psilostrophe tagetina. Within about of the New Mexico–Texas border the two intergrade, and in 1988 B. L. Turner and colleagues treated P. villosa as a variety of P. tagetina, P. tagetina var. cerifera. The Flora of North America and the Integrated Taxonomic Information System both treat it as a separate species.
Distribution and habitat
Psilostrophe villosa is native to the United States, where it has been recorded in Kansas, New Mexico, Oklahoma and Texas. In the Trans-Pecos region of Texas it has been collected within about of the Rio Grande, and the Flora of North America suggests it probably also occurs in Mexico. It grows in grasslands on limestone and gypsum soils and on caliche, at elevations of . It flowers mainly from May to August, though flowering has been recorded from March to October.