Erigerons have yellow disk flowers and numerous, narrow ray flowers that are white, pink, or purple (but not yellow).

     Linnaeus named this genus in 1753.  The genus name is from the Greek "eri" ("early") + "geron" ("old man", as in "geriatrics"), perhaps referring to characteristics of some now unknown plant or perhaps to the early flowering of many species and to the bristly pappus of the developing seed or to the puffy, grizzled appearance of the mature seed head.

Subalpine, alpine.  Meadows.  Summer.
American Basin, July 24, 2007.

This is a fairly common Erigeron on rocky tundra.  It grows to just five inches tall yet has flower heads an inch across so it easily attracts your attention.  Look for it above tree-line on rocky outcrops.  The finely cut leaves and large flower heads are hallmarks.  It is found throughout the Colorado Rockies, in three northern counties in New Mexico, and is rare in just two southern counties in Wyoming. 

The plant was most likely first collected on the Wheeler Exploring Expedition of 1873-1875 by Franz Wolf (1841-1924) and Dr. Joseph Rothrock (1839-1922, surgeon and botanist with the Wheeler Expedition, Professor of Botany at the University of Pennsylvania, and considered the father of Pennsylvania forestry).  In 1880 Asa Gray named this plant Erigeron compositus var. pinnatisectus.  In 1899 Aven Nelson renamed it Erigeron pinnatisectus.

Subalpine, alpine.  Meadows.  Summer.
American Basin, July 24, 2007.