Note the flattened siliques...so this is Streptanthus, rather than Caulanthus. (The two are sometimes easy to confuse...and W. L. Jepson himself treated them together as a single genus! See 2nd through 4th paragraphs here.)

Note, on the right portion of the image, the slightly elevated woody caudex below lowest leaves (cf. the last character in the terminal couplet for S. bernardinus in the current Jepson Manual II treatment.)

This plant keys fairly well to Streptanthus bernardinus (better than to any other taxa listed in the JM2 key). However, the JM2 description indicates that (lower) leaves have ''petioles ciliate''. I see no petioles on any leaves here, let alone cilia.

Note that my my older posts from the San Bernardino Mountains may be a different taxon, though the best I could do to fit them into existing treatments was Streptanthus bernardinus. (In personal communications, Roy Buck, agreed that my San Bernardino specimens were peculiar...and perhaps something different...but seemed to fit best with S. bernardinus under the existing treatment.) The posts of Thomas Stoughton seem to vary somewhat from the specimens I've posted as well. This taxon seems fairly variable (perhaps ripe for splitting?).