Southwest Colorado Wildflowers, Erigerons, White 2

Erigerons, what we often call "Daisies", are a large and complex genus with several dozen species common in the Four Corners. Erigerons have yellow disk flowers and numerous narrow ray flowers that are white, pink, or purple (but not yellow).

In 1753 Linnaeus gave the genus its name from the Greek "eri" ("early") + "geron" ("old man" -- "geriatrics" is the study of old age processes and problems). Perhaps the Greek name refers 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.

Erigeron coulteri (Coulter’s Daisy)
Asteraceae (Sunflower Family)

Subalpine. Meadows, woodlands. Summer.
Middle Calico Trail, August 9, 2004.

Coulter’s Daisy is common in high mountain dry and moist meadows and open Spruce woods. It grows singly and widely scattered in open woods or more densely in sunny open meadows. Each plant generally bears one long-lasting flower. Basal leaves are often withered by flowering time. In late July, August, and into September Erigeron coulteri is often the most common white flower in the mountains.

John Coulter collected this plant in Colorado and it was described and named for him by Thomas Porter who, with Coulter, in 1874 authored the first Colorado floral guide, Synopsis of the Flora of Colorado. (More biographical information.)

Erigeron coulteri (Coulter’s Daisy)
Asteraceae (Sunflower Family)

Subalpine. Meadows, woodlands. Summer.
Colorado Trail above Roaring Fork, July 26, 2004.
Turkey Springs Trail, June 26, 2007.

Erigerons often unfold in a humorous fashion. The bright white ray flowers contrast sharply with the dark hairs on the phyllaries. See third photograph at left.

Note the presence of both light and dark shaggy hairs on the flower stem and phyllaries in the third photograph. Most botanical keys indicate that Erigeron coulteri hairs have "black crosswalls". These crosswalls (under high magnification they appear as horizontal rings around the vertical hairs) really cannot be observed in the field -- even with a 10x hand lens. At twenty-to-forty power magnification with a microscope, one can see that some hairs are dark (maroon-black); some hairs are dark on the bottom and a gelatinous white on the top; some are white with black crosswalls; some are dark from bottom to top; etc. Most do have black, or sometimes white, crosswalls.

Erigeron eatoni
Asteraceae (Sunflower Family)

Foothills, montane. Meadows, Oak brush. Spring, summer.
Northeast corner of Navajo Reservation, June 3, 2006.

Erigeron eatoni's stems arch out from a central base and its long, three-nerved, grass-like basal leaves also arch.

The plant is most often found in sagebrush country but it is also occasionally found at higher elevations. Flowers are about a half-inch in diameter.

Asa Gray named this plant in 1880 from a specimen collected by Sereno Watson in Utah. Daniel Eaton was a 19th century Professor of botany at Yale. (More biographical information.)