Fire Poppy. As far as I can tell this only blooms in the years immediately after a fire. I’d never seen it before 2010 when it appeared in the region of the Jesusita burn first on Cold Spring trail, west fork, in the region the fire burned and about a fortnight later on Jesusita trail.
The flower has 4 petals and 2 sepals which look exactly like the petals — except that the sepals are very loosely attached to the flower and fall off if the flower is touched.
In 2010 it was blooming in March (didn’t look before then). Very few left in mid-May. All gone by June. In 2011 saw one bloom on West Fork at the end of January. I have seen none since.