California poppies are surprisingly rare on our trails, actually we don’t have the true California Poppy, but one of its cogeners, the collarless California poppy. In 2010 I found a small patch on west fork of Cold Spring trail (in the burn area) and another patch on Tunnel trail about 1/4 mile before the Rattlesnake connector and a third patch on upper San Ysidro, and a fourth on the back side of Cold Spring. In 2011 I also found blooms on Rattlesnake just below the Meadow.
On the trails it seems to bloom January through early July, but the More Mesa patch bloomed into September.
It may be distinguished from the true California poppies (E. californica) because it does not have a small torus underneath the bloom (and because it blooms are yellow while the true California poppy is variable in color)