brown-eyed evening-primrose
Chylismia claviformis ssp. claviformis
(right and below)

shredding evening-primrose
Eremothera boothii ssp.condensata
(right)

Both of these species in the Onagraceae are annuals found in various deserts of the American West. I spent some time trying to find interesting facts about them, but came up with very little. According to Pam Mackay’s Mojave Desert Wildflowers: A Field Guide to Wildflowers, Trees, and Shrubs, brown-eyed evening primrose has an extremely high photosynthetic rate. Also, the plant is favored by white-lined sphinx moth larvae, a fact that reminded me of a few photos I took of caterpillars, like this one:

There seems to be some morphological variation in these, so I’m not positive of the identification. But it was hanging around the brown-eyed evening primroses…