notes Postscript (12/22/19): This previously problematic taxonomic entity has now been recognized and described as a new species (to be called Streptanthus juneae) as resolved in a paper by Nick Jensen to appear shortly in MadroƱo (already submitted, reviewed, and accepted...just awaiting printing date & distribution). Yay! Thanks to Nick for his careful work and insights on this species and the 'S. howellii alliance' to which it belongs.
Postscript (4/25/20): Name now officially published :-) Link to Nick's paper here.
Original remarks from 5/17/2006 appear below...
Habit shot.
I am not certain of the identity of this plant (cf. last paragraph of comments under my later post here), but my best guess is Streptanthus bernardinus. One of my hesitations comes from the fact that both the Jepson Manual and Munz state that S. bernardinus has ''white petals'', whereas this taxon clearly has yellow petals w/ purple tips. But the last key break leading to S. bernardinus in the Jepson manual also says:
''11. Petals light greenish-yellow...S.bernardinus''
...which makes the ''petals white'' character mentioned in the descriptions less compelling.
In most other respects, the description, habitat and location all seem compatible with S. bernardinus. It's worth mentioning that S. bernardinus is a rare plant and this location is east of other known locations for the San Bernadino Mnts listed in the Calflora database.