Oenothera pallida Lindl. subsp. trichocalyx (Engelm.) Munz & W.Klein
As the name suggests, it differs from other Oenothera pallida in having a prominently pubescent calyx. Easily confused with Oenothera albicaulis in keys, but more readily separated on gestalt...
Plant habit near the Colorado River northeast of Moab, Grand County, Utah, 16 Jun 2006.
A flower near the Colorado River, 16 Jun 2006.
Buds, showing pubescent calyces, near the Colorado River, 16 Jun 2006.
Flowers near the Colorado River, 16 Jun 2006.
Immature fruit near the Colorado River, 16 Jun 2006.