Agoseris aurantiaca var. purpurea
Rhodora 50: 33. 1948
Phenology: Flowering Jun–Sep.
Habitat: Moist, subalpine meadows and forests to alpine tundra, often disturbed areas
Elevation: 1800–3600 m
Ariz., Colo., Nev., N.Mex., Utah, Wyo.
Variety purpurea is known mainly from the Colorado Plateau and southern Rocky Mountains. The two varieties are partially sympatric in the mountains of Colorado, Utah, southern Wyoming, and northern New Mexico, </i>var.<i> aurantiaca occurring only at very high elevations in that region. Wherever </i>var.<i> purpurea and </i>var.<i> aurantiaca occur together, they intergrade. Hybrids between </i>var.<i> purpurea and A. glauca or A. parviflora occur. One hybrid has been named (as a species): Agoseris aurantiaca var. purpurea × A. glauca var. dasycephala (= A. ×montana Osterhout) occurs sporadically at high elevations in the Rocky Mountains of Colorado.
Variety purpurea tends to exhibit a higher frequency of yellow-flowered populations than </i>var.<i> aurantiaca. Plants of </i>var.<i> purpurea from the Rocky Mountains usually have orange corollas; those from the plateaus of southern Utah and northern Arizona often have yellow corollas. These more southwestern populations have been called A. arizonica (or A. purpurea </i>var.<i> arizonica); the two regional phases cannot be adequately separated and their segregation is arbitrary.