[Wikipedia] Description, Rarity: 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. It is an annual herb producing a small stem up to 8 or 9 centimeters tall with a bristly base. The toothed oval leaves are under 2 centimeters long. The inflorescence is a cluster-like raceme of flowers, the top ones sterile. The fertile flowers on the lower raceme have calyces of bristly purple-green sepals under a centimeter long with flaring purple petals at the tip. The sterile flowers at the top of the raceme have narrow, elongated, hairless purple sepals. The fruit is a cylindrical, bristle-studded silique measuring up to 2 or 2.5 centimeters long. (contributed by Mary Ann Machi)