Streptanthus howellii
Encyclopedia
Streptanthus howellii is an uncommon species of flowering plant in the mustard family
known by the common name Howell's jewelflower. It is endemic to the Klamath Mountains
of southern Oregon
and northern California
. It grows in mountain forests on serpentine soil
s. It is a perennial herb producing a hairless, often waxy-textured stem up to 70 or 80 centimeters in maximum length. It is generally unbranched. The ephemeral basal leaves have fleshy oval blades with smooth or toothed edges, borne on petioles
. Leaves farther up the stem are similar but smaller and narrower, with shorter petioles or none. They do not clasp the stem. Flowers occur at intervals along the upper stem. Each has a calyx of purple sepal
s under a centimeter long with purple-tipped yellow petals emerging from the tip. The fruit is a thin, smooth, curved silique
up to 12 centimeters long.
This rare plant is threatened by wildfire suppression; it would be more common if its habitat were allowed its natural fire regime
. It is also threatened by mining
operations.
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 Howell's jewelflower. It is endemic to the Klamath Mountains
Klamath Mountains
The Klamath Mountains, which include the Siskiyou, Marble, Scott, Trinity, Trinity Alps, Salmon, and northern Yolla-Bolly Mountains, are a rugged lightly populated mountain range in northwest California and southwest Oregon in the United States...
of southern Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
and northern California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
. It grows in mountain forests on serpentine soil
Serpentine soil
A serpentine soil is derived from ultramafic rocks, in particular serpentinite, a rock formed by the hydration and metamorphic transformation of ultramafic rock from the Earth's mantle....
s. It is a perennial herb producing a hairless, often waxy-textured stem up to 70 or 80 centimeters in maximum length. It is generally unbranched. The ephemeral basal leaves have fleshy oval blades with smooth or toothed edges, borne on petioles
Petiole (botany)
In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...
. Leaves farther up the stem are similar but smaller and narrower, with shorter petioles or none. They do not clasp the stem. Flowers occur at intervals along the upper stem. Each has a calyx of purple 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 purple-tipped yellow petals emerging from the tip. The fruit is a thin, smooth, curved 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...
up to 12 centimeters long.
This rare plant is threatened by wildfire suppression; it would be more common if its habitat were allowed its natural fire regime
Fire regime
A fire regime is the pattern, frequency and intensity of the bushfires and wildfires that prevails in an area. It is an integral part of fire ecology, and renewal for certain types of ecosystems. If fires are too frequent, plants may be killed before they have matured, or before they have set...
. It is also threatened by mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
operations.