Wednesday

Whitebract Blazingstar (Mentzelia involucrata)

EFP-P1010099
(Fig. 01)
Picture Notes: I have actually had several siting's of this plant. The largest specimen I encountered, shown in (Fig. 01), was captured on 05/16/13 while hiking down a ledge filled wash that was descending from the Yucca Peak Fossil Beds just below Yucca Peak in the Desert National Wildlife Range. The one in (Fig. 02) and close-ups (Fig. 03 & 04), were as taken along Calleville Wash North Road near the Bowl of Fire area.
             
EFP-P1110157
(Fig. 02)
Description: The Whitebract Blazingstar (Mentzelia involucrata) is an uncommon annual forb that looks like a small, rounded shrub (a mound of crinkled leaves) topped with large, cup-shaped, pale yellow flowers. The medium-sized leaves are hairy, and the flowers have five petals and many stamens. Its stems are thick, but not woody. Its hairy leaves are irregularly toothed, alternate, linear to oval, and are about 3./4 of an inch long.  Its inflorescence, single pale yellow flowers have 5 petals, from 1/2 to 2-1/2 inches, and contain 1-inch stamens. They bloom in early to late spring. With a distribution from Nevada to California, and south into Mexico, it can be found on dry, well-drained sandy and gravelly desert flats, bajadas, washes and moderate slopes in the lower mountains of the Lower Sonora (Creosote-Bursage Flats) and Upper Sonoran (Mojave Desert Scrub) life zones at elevations to about 3,000 feet.
EFP-P1110158
(Fig. 03)
EFP-P1110161
(Fig. 04)