Psilostrophe bakeri

Psilostrophe bakeri, commonly known as Baker's paperflower, is a species of flowering plant in the family Asteraceae. It is native to Colorado and Idaho in the western United States.

Description

Psilostrophe bakeri is a biennial or perennial herb that rarely flowers during its first year. It usually grows tall, though it may exceed . Its stems are gray to gray-green and covered with cobwebby hairs. The flower heads are arranged in loose, flat-topped clusters on stalks generally long. Each head usually has four or five yellow ray florets, occasionally as many as eight, surrounding 10–20 disc florets. The fruits are cypselae, usually hairless and sometimes dotted with glands, with a pappus of four or five oblong scales. Its chromosome number is 2n = 32.

Taxonomy

American botanist Edward Lee Greene published the species in Plantae Bakerianae in 1901. The lectotype was collected near Montrose, Colorado, by C. F. Baker as collection number 14. Psilostrophe pumila, described by Aven Nelson in 1903, is treated as a synonym by Plants of the World Online. The common name recognized by the Integrated Taxonomic Information System is Baker's paperflower.

Distribution and habitat

The species is native to Colorado and Idaho. It grows on rocky, often alkaline slopes and knolls at elevations of . Flowering occurs in May and June. An annotated checklist for Colorado National Monument records the species as present, regionally endemic, and rare within the monument.