Largeflower hawksbeard (Crepis occidentalis)

Abstract

Largeflower hawksbeard has a widespread western distribution from British Columbia to Saskatchewan in the north to South Dakota in the east and in New Mexico, Arizona, and California in the south (Hermann 1966; Bogler 2006). Populations are most common in the Columbia Plateau and Great Basin and frequent in northern California and southern Oregon (Babcock and Stebbins 1938; Sears and Whitton 2016). Subspecies occidentalis occurs throughout the species range (Bogler 2006). Subspecies conjuncta occurs in Washington, Montana, Wyoming, Colorado, California, and Oregon. Subspecies costata occurs in British Columbia, Saskatchewan, Montana, Wyoming, Colorado, Utah, Nevada, California, Oregon, Washington, and Idaho. Subspecies pumila occurs in British Columbia, Washington, Oregon, Idaho, Montana, Utah, Nevada, and California (Bogler 2006). Babcock and Stebbins (1938) suggest that largeflower hawksbeard is one of the most widespread and perhaps the most polymorphic of the American hawksbeards (Crepis spp.). In a thorough study of the species, they mapped the distribution of the polyploid and apomictic forms (Fig. 1). The diploid sexual form has a very restricted distribution, occurring at elevations of 3,900 to 5,200 ft (1,200-1,600 m) on the arid east side of the Sierra Nevada Range in northeastern California and adjacent Nevada. Polyploid forms, especially those with chromosome numbers of 2n = 33 or 44 occurred nearly throughout the species range. Polyploids with higher chromosome numbers were less widespread and tended to be more abundant near the centers of the subspecies’ distributions (Babcock and Stebbins 1938).

Parent Publication

• Western forbs: Biology, ecology, and use in restoration - Project Overview and Acknowledgements

Citation

Gucker, Corey L.; Shaw, Nancy L. 2024. Largeflower hawksbeard (Crepis occidentalis). In: Gucker, C.L.; Shaw, N.L., eds. Western forbs: Biology, ecology, and use in restoration. Reno, NV: Great Basin Fire Science Exchange. Online: https://westernforbs.org/species/largeflower-hawksbeard-crepis-occidentalis/.