Thelypodium stenopetalum
Encyclopedia
Thelypodium stenopetalum is a rare species of flowering plant in the mustard family
known by the common names slenderpetal thelypody and slender-petaled mustard. It is endemic to the San Bernardino Mountains
of southern California
, where it is known from only three or four extant occurrences in moist mountain meadows near Big Bear Lake
. Its remaining habitat is considered seriously threatened and the plant is a federally listed endangered species
in the United States. It is a biennial herb producing decumbent stems up to about 80 centimeters long. The branching stems are hairless, waxy in texture, and greenish to purple in color. The basal leaves have thick, oblong to lance-shaped blades up to 15 centimeters long with smooth or rippled edges. Leaves higher on the plant have much smaller blades which may clasp the stem at their bases. The inflorescence
is an erect, open raceme
of widely spaced flowers. The petals are usually lavender, or occasionally white, and are narrow and linear in shape, sometimes crinkled. The fruit is a narrow, cylindrical silique
up to 5 centimeters long.
This plant is threatened by the destruction of its very limited mountain meadow habitat, which is being claimed for development and degraded by recreation, grazing, and introduced weedy plants
. Changes in hydrology
and soil quality impact the plant. Much of its historical habitat is thought to have disappeared when the Big Bear Dam was built over a century ago, expanding Big Bear Lake by flooding adjacent land. It can sometimes be found growing near pebble plain habitat, which contains several other rare plant species. This mustard is a food plant for the larva of the rare endemic Andrew's marble butterfly
(Euchloe hyantis andrewsi).
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 names slenderpetal thelypody and slender-petaled mustard. It is endemic to the San Bernardino Mountains
San Bernardino Mountains
The San Bernardino Mountains are a short transverse mountain range north and east of San Bernardino in Southern California in the United States. The mountains run for approximately 60 miles east-west on the southern edge of the Mojave Desert in southwestern San Bernardino County, north of the...
of southern 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 is known from only three or four extant occurrences in moist mountain meadows near Big Bear Lake
Big Bear Lake
Big Bear Lake is a reservoir in the San Bernardino Mountains, in San Bernardino County, California, United States. At a surface elevation of , it has an east-west length of approximately 7 miles and is approximately 2.5 miles at its widest measurement, though the lake's width mostly averages a...
. Its remaining habitat is considered seriously threatened and the plant is a federally listed endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
in the United States. It is a biennial herb producing decumbent stems up to about 80 centimeters long. The branching stems are hairless, waxy in texture, and greenish to purple in color. The basal leaves have thick, oblong to lance-shaped blades up to 15 centimeters long with smooth or rippled edges. Leaves higher on the plant have much smaller blades which may clasp the stem at their bases. 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 an erect, open 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 widely spaced flowers. The petals are usually lavender, or occasionally white, and are narrow and linear in shape, sometimes crinkled. The fruit is a narrow, cylindrical 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 5 centimeters long.
This plant is threatened by the destruction of its very limited mountain meadow habitat, which is being claimed for development and degraded by recreation, grazing, and introduced weedy plants
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
. Changes in hydrology
Hydrology
Hydrology is the study of the movement, distribution, and quality of water on Earth and other planets, including the hydrologic cycle, water resources and environmental watershed sustainability...
and soil quality impact the plant. Much of its historical habitat is thought to have disappeared when the Big Bear Dam was built over a century ago, expanding Big Bear Lake by flooding adjacent land. It can sometimes be found growing near pebble plain habitat, which contains several other rare plant species. This mustard is a food plant for the larva of the rare endemic Andrew's marble butterfly
Euchloe hyantis
Euchloe hyantis, the Pearly Marble, Pearly Marblewing or California Marble, is a butterfly in the Pieridae family. It is found from southern Oregon south through California west of the Sierra Nevada crest to northern Baja California. The habitat consists of rocky canyons, cliffs, moraines and...
(Euchloe hyantis andrewsi).