Flowers are cadmium-yellow, fading old-rose, 2½ inches across, of 4 wide petals. The 4 narrow sepals bend back and at their base merge into a hollow tubular stem. The style branches at its tip into 4 conspicuous slender stigmas. Plant has little or no main stem; leaves are dark-green, strap-shaped, 3 inches long. Grows in foothills, but only where soil is somewhat marly. Blooms May-June.

Look for this one of our numerous evening-primroses about Memorial Day. Soil formed from the disintegration of Niobrara shale such as we find along the Hogsback near Denver, or along the Boulder-Lyons road, is its preference. The plants are rather ragged, but the flowers draw all our attention to their soft, clear yellow as they spread open in the sunshine. They last but a day—fading into soft rosy colors. The white members of this family are much better known. Several such species common on the plains are so responsive to early summer rain that within days after a good shower all our roadsides and even vacant lots will be gay with their short-lived beauty.