Streptanthus callistus
Encyclopedia
Streptanthus callistus is a rare species of flowering plant in the mustard family
known by the common name Mount Hamilton jewelflower. It is endemic to Santa Clara County, California
, where it is known from only about five occurrences around Mount Hamilton
. 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 sepal
s 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.
Brassicaceae
Brassicaceae, a medium sized and economically important family of flowering plants , are informally known as the mustards, mustard flowers, the crucifers or the cabbage family....
known by the common name Mount Hamilton jewelflower. It is endemic to Santa Clara County, California
Santa Clara County, California
Santa Clara County is a county located at the southern end of the San Francisco Bay Area in the U.S. state of California. As of 2010 it had a population of 1,781,642. The county seat is San Jose. The highly urbanized Santa Clara Valley within Santa Clara County is also known as Silicon Valley...
, where it is known from only about five occurrences around Mount Hamilton
Mount Hamilton (California)
Mount Hamilton is a mountain in California's Diablo Range, in Santa Clara County, California. Mount Hamilton, at is the tallest mountain overlooking Silicon Valley, and is the site of Lick Observatory, the first permanently occupied mountain-top observatory. The various summits along its...
. It grows in chaparral
Chaparral
Chaparral is a shrubland or heathland plant community found primarily in the U.S. state of California and in the northern portion of the Baja California peninsula, Mexico...
and woodlands and on dry scree
Scree
Scree, also called talus, is a term given to an accumulation of broken rock fragments at the base of crags, mountain cliffs, or valley shoulders. Landforms associated with these materials are sometimes called scree slopes or talus piles...
. 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
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
is a cluster-like raceme
Raceme
A raceme is a type of inflorescence that is unbranched and indeterminate and bears pedicellate flowers — flowers having short floral stalks called pedicels — along the axis. In botany, axis means a shoot, in this case one bearing the flowers. In a raceme, the oldest flowers are borne...
of flowers, the top ones sterile. The fertile flowers on the lower raceme have calyces of bristly purple-green sepal
Sepal
A sepal is a part of the flower of angiosperms . Collectively the sepals form the calyx, which is the outermost whorl of parts that form a flower. Usually green, sepals have the typical function of protecting the petals when the flower is in bud...
s 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
Silique
A silique or siliqua is a fruit of 2 fused carpels with the length being more than three times the width. The outer walls of the ovary usually separate when ripe, leaving a persistent partition...
measuring up to 2 or 2.5 centimeters long.