Streptanthus callistus is an annual herb that is native to California, and endemic (limited) to California.
California Rare Plant Rank: 1B.2 (rare, threatened, or endangered in CA and elsewhere).
[Wikipedia] Rarity, Habitat: Streptanthus callistus is a rare species of flowering plant in the mustard family known by the common name Mount Hamilton jewelflower.[1] It is endemic to Santa Clara County, California, where it is known from only about five occurrences around Mount Hamilton.[2] It grows in chaparral and woodlands and on dry scree. (link added by Mary Ann Machi)
Calflora:
Information on California plants for education, research and conservation,
with data contributed by
public and private institutions and individuals.
[web application]. 2025.The Calflora Database
[a non-profit organization].Available:
https://www.calflora.org/(Accessed: 03/29/2025).