Arenaria ursina
Encyclopedia
Arenaria ursina is a species of flowering plant in the pink family
known by the common name Bear Valley sandwort.
, where it is known from a few occurrences in the vicinity of Big Bear
. It grows on quartzite
pebble plain habitat in forest openings in the San Bernardino Mountains
near the communities of Fawnskin
, Sugarloaf
, and Baldwin Lake
. It is an indicator species for the rare pebble plain habitat, which is unique to the area. It is a federally listed threatened species
.
is an open cyme of white flowers with five petals each under half a centimeter long and protruding purple-anthered stamen
s. The fruit is a toothed capsule containing 1 or 2 minute purple seeds.
. Other threats include destruction of its habitat for development, mining activity, and disturbance of the landscape during fire suppression efforts.
Caryophyllaceae
The Caryophyllaceae, commonly called the pink family or carnation family, is a family of flowering plants. It is included in the dicotyledon order Caryophyllales in the APG III system, alongside 33 other families, including Amaranthaceae, Cactaceae and Polygonaceae...
known by the common name Bear Valley sandwort.
Distribution
It is endemic to San Bernardino County, CaliforniaSan Bernardino County, California
San Bernardino County is a county in the U.S. state of California. As of the 2010 census, the population was 2,035,210, up from 1,709,434 as of the 2000 census...
, where it is known from a few occurrences in the vicinity of Big Bear
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...
. It grows on quartzite
Quartzite
Quartzite is a hard metamorphic rock which was originally sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to gray, though quartzites often occur in various shades of pink...
pebble plain habitat in forest openings in 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...
near the communities of Fawnskin
Fawnskin, California
Fawnskin is an unincorporated community in San Bernardino County, California, United States. Its altitude is 6,827 feet . The community has a post office, which was established on 18 May 1918.-History:...
, Sugarloaf
Sugarloaf, California
Sugarloaf is an unincorporated residential area less than a mile south of Big Bear City and 8 miles from the eastern tip of Big Bear Lake in the San Bernardino Mountains of San Bernardino County, California. The area is primarily residential with a convenience store and a bar located at the center...
, and Baldwin Lake
Baldwin Lake, California
Baldwin Lake is a natural, intermittent, alkali lake in a valley of the San Bernardino Mountains, in San Bernardino County, California. The depth of Baldwin Lake's lowest point is approximately 25 feet . At its widest, the lake is more than a mile across...
. It is an indicator species for the rare pebble plain habitat, which is unique to the area. It is a federally listed threatened species
Threatened species
Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...
.
Description
Arenaria ursina is a petite perennial herb forming small tufts no more than 18 centimeters tall. Its small, waxy leaves are needlelike and up to a centimeter long. The inflorescenceInflorescence
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 open cyme of white flowers with five petals each under half a centimeter long and protruding purple-anthered stamen
Stamen
The stamen is the pollen producing reproductive organ of a flower...
s. The fruit is a toothed capsule containing 1 or 2 minute purple seeds.
Threats
The biggest threat to the survival of this species is off-roadingOff-roading
Off-roading is a term for driving a vehicle on unsurfaced roads or tracks, made of materials such as sand, gravel, riverbeds, mud, snow, rocks, and other natural terrain.-Off-road vehicle:...
. Other threats include destruction of its habitat for development, mining activity, and disturbance of the landscape during fire suppression efforts.