Family: Stick Leaf (Loasaceae)
Size: To 2 in. wide
Notes: While this flower appears to have 10 petals, the larger 5 are actually the calyx, whose inner surface is the same color as the petals. The seed capsule is bullet shaped. The flower is only open for a couple of hours a day, opening in late afternoon and closing at sunset. Apparently the bees don't mind this behavior. 11 species of Mentzelia in Arizona.
This plant is found on the Appleton-Whittell Research Ranch Working Check list of flora.