Cryptantha pterocarya
ANNUAL.  One of the few Cryptantha that is easy to identify.  Tiny white flowers sit atop swollen, sparsely bristly, five-sided oval calyces on nearly bare stems.  Blooms in March-April and gone by the end of May.  Very common on gravel, disturbed ground, etc.
FAMILY:  Boraginaceae (Forget-me-not Family)

Cryptantha species have tiny white five-petaled flowers that are often hidden in the urn-shaped bristly calyces that crowd the stem.  Plants are inconspicuous unless they appear in large numbers, as they often do on disturbed ground in early spring.  Several species are usually found growing together, often with Lappula and one or more Pectocarya species.  Most species look very similar and are quite variable in size and growth form depending on availability of water and the age of the plant.  They are difficult to identify, requiring careful examination of the bracts, seeds, and growth habit.