Stem & Leaves of Western Larkspur (Delphinium hesperium ssp. hesperium) (?)
Western larkspur only grows on serpentine soil. Trail 15, at least near serpentine soil. (Is that a serpentine rock in the background?) If I am mistaken about the soil type, this may be spreading or zigzag larkspur, D. patens ssp. patens, which does not grow on serpentine.