Streptanthus breweri
Encyclopedia
Streptanthus breweri is a species of flowering plant in the mustard family
known by the common name Brewer's jewelflower. It is endemic to California
, where it can be found in the coastal mountain ranges from the Klamath Mountains
south to the San Francisco Bay Area
. Its habitat includes chaparral
and woodlands, usually on serpentine soil
s. It is an annual herb producing an erect, branching stem up to about 80 centimeters in maximum height. It is hairless except for fine hairs on some of the inflorescence
parts, and it may be waxy in texture. The basal leaves have oval blades borne on petioles
, and the lance-shaped leaves farther up the stem clasp it at their bases. Flowers occur at intervals along the upper stem, sometimes in a zig-zagging, one-sided array. Each has an urn-shaped calyx of keeled greenish or purplish sepal
s under a centimeter long. White, purple, or purple-veined white petals emerge from the tip. The fruit is a narrow, curved silique
which may be 9 to 11 centimeters in length.
The leaves of the plant sometimes have hardened, orange-pigmented callosities
on the blades which are thought to be egg-mimics. Female California White
butterflies (Pontia sisymbrii syn. Pieris s.) lay eggs
on Streptanthus leaves, and they choose leaves that have not yet had eggs deposited on them. Each larva
can easily eat a whole plant, and the butterfly performs an "egg-load assessment" to determine the potential competition for its larva. Leaves that have grown callosities, which strongly resemble the orange eggs of the butterfly, are less likely visited by egg-laying females, protecting the plant from herbivory.
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 Brewer's jewelflower. It is endemic to 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...
, where it can be found in the coastal mountain ranges from 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...
south to the San Francisco Bay Area
San Francisco Bay Area
The San Francisco Bay Area, commonly known as the Bay Area, is a populated region that surrounds the San Francisco and San Pablo estuaries in Northern California. The region encompasses metropolitan areas of San Francisco, Oakland, and San Jose, along with smaller urban and rural areas...
. Its habitat includes 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, usually 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 an annual herb producing an erect, branching stem up to about 80 centimeters in maximum height. It is hairless except for fine hairs on some of 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...
parts, and it may be waxy in texture. The basal leaves have oval blades 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...
, and the lance-shaped leaves farther up the stem clasp it at their bases. Flowers occur at intervals along the upper stem, sometimes in a zig-zagging, one-sided array. Each has an urn-shaped calyx of keeled greenish or purplish 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. White, purple, or purple-veined white petals emerge from the tip. The fruit is a narrow, 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...
which may be 9 to 11 centimeters in length.
The leaves of the plant sometimes have hardened, orange-pigmented callosities
Callus
A callus is an especially toughened area of skin which has become relatively thick and hard in response to repeated friction, pressure, or other irritation. Rubbing that is too frequent or forceful will cause blisters rather than allow calluses to form. Since repeated contact is required, calluses...
on the blades which are thought to be egg-mimics. Female California White
Pontia sisymbrii
The Spring White, California White, or Colorado White is a butterfly in the family Pieridae. It is found in mountainous areas of western Canada and the USA....
butterflies (Pontia sisymbrii syn. Pieris s.) lay eggs
Oviposition
Oviposition is the process of laying eggs by oviparous animals.Some arthropods, for example, lay their eggs with an organ called the ovipositor.Fish , amphibians, reptiles, birds and monetremata also lay eggs....
on Streptanthus leaves, and they choose leaves that have not yet had eggs deposited on them. Each larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
can easily eat a whole plant, and the butterfly performs an "egg-load assessment" to determine the potential competition for its larva. Leaves that have grown callosities, which strongly resemble the orange eggs of the butterfly, are less likely visited by egg-laying females, protecting the plant from herbivory.