sinuata or Mentzelia sinuata
is found only along the foothills of the northern Front Range, primarily on shale
outcrops. The bright yellow flowers open in the evening, so plants are usually
seen with closed flowers. Plants grow to a height of 8 to 30 inches. Look for
it on roadcuts on the east side of Horsetooth Reservoir.
Mentzelia sinuata is very similar to Mentzelia multiflora (not
pictured). M multiflora has lighter colored flowers. For positive identification,
the species are separated by looking at the texture of the seed coat under magnification.