Habitat Preferences: Lower and upper deserts, pinyon-juniper, chaparral vegetation; Creosote Bush (Larrea) communities, washes, rocky, sandy and gravelly areas.
Recorded Range: Distribution limited in the United States to the southwestern states of AZ, CO, NM and UT. Found mostly in central and northern AZ and southeast UT, with much smaller populations in southwest CO and northwest NM. Rusby's Goldenbush is also native to northwest Mexico.
North America species range map for Rusby's Goldenbush, Isocoma rusbyi:
North American range map courtesy of Virginia Tech, Dept. of Forest Resources & Environmental Conservation
Click image for full size map
Genus Information: In North America there are 11 species and 11 accepted taxa overall for Isocoma. Worldwide, The Plant List includes 15 accepted species names and a further 44 scientific names of infraspecific rank for Isocoma.
In the Southwestern United States: Arizona has 5 species of Isocoma, California, Utah and Texas each have 3 species, Nevada has 1 species and New Mexico has 4 species. Data approximate and subject to revision.
Comments: Rusby's Goldenbush is a fall blooming yellow daisy formerly included in the genus Haplopappus called Rabbitbrush and Goldenweed. This species and several others were reclassified to Isocoma and other genera.
Rusby's Goldenbush, Isocoma rusbyi, is apparently toxic to livestock; the flowers, seeds and plants may be visited by hummingbirds and/or small mammals including rodents in search of food, nectar, shelter and protection through cover.
Beneficial Value to Butterflies, Bees and Insects
Rusby's Goldenbush, Isocoma rusbyi, brightly colored flowers and plants attracts butterflies, moths and other insects in search of food, nectar or shelter.
The genus “Isocoma” (Isoco'ma:) is from the Greek meaning “an equal hair-tuft,” and referring to the flowers.