Calystegia purpurata purpurata

Pacific False Bindweed, Pacific Morning Glory. I have not noticed this in the front country, but it’s on the other side of Camino Cielo (and up to to top of the mountains)

Large white flowers. (There are said to be pink and purple variants, but I haven’t seen any locally).

Blooms all year, but is at its peak around May.

May be distinguished from C. macrostegia by the bracts at the base of the flower. In this species the bracts look like tiny little leaves a few millimeters below the flower, while in C. macrostegia the bracts surround, and mostly obscure, the calyx (the sepals at the base of the flower). Also can grow higher up the mountain.