Cistanthe pulchella
Encyclopedia
Cistanthe pulchella is a rare species of flowering plant in the purslane family
known by the common name Mariposa pussypaws. It is endemic to the Sierra Nevada foothills of central California
, where it is known from only a few scattered occurrences. It grows on barren patches of granite
gravel in woodland and grasslands. It is a federally listed threatened species.
is a number of spherical clusters of rose-colored petals and thin sepal
s. The fruit is a tiny translucent capsule containing one or two seeds.
of seeds and the growth of seedling
s. Past total population estimates varied from 1680 to nearly 3000 individuals. Some populations are located on private land and have not been surveyed in many years. Others are quite variable in size, increasing from 58 to 770 individuals, or decreasing from hundreds of plants to only 3.
A major threat to this species is habitat fragmentation
; populations have been bisected by road
s, dirtbike trails, and firebreak
s. At least two populations are in the middle of residential subdivisions
, or on the edges; these may be extirpated
by now. Residential and commercial development continue to claim the habitat, as does the expansion of infrastructure
to support the new development, including local services, utilities
, and roads. Livestock
are allowed to graze
in some areas, but it is unknown if this affects the species. Since most of the populations are small, they are vulnerable to destruction from any one severe local event, such as drought
or disease, and since the populations sometimes fall to very low numbers they are at risk for genetic bottlenecks
and genetic drift
.
Portulacaceae
Portulacaceae are a family of flowering plants, comprising about 20 genera with about 500 species, ranging from herbaceous plants to shrubs. The family has been recognised by most taxonomists, and is also known as the purslane family; it has a cosmopolitan distribution, with the highest diversity...
known by the common name Mariposa pussypaws. It is endemic to the Sierra Nevada foothills of central 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 a few scattered occurrences. It grows on barren patches of granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
gravel in woodland and grasslands. It is a federally listed threatened species.
Description
It is a very small red-green annual plant radiating spreading stems a few centimeters long. There is a basal rosette of tiny, thick leaves. 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 a number of spherical clusters of rose-colored petals and thin 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. The fruit is a tiny translucent capsule containing one or two seeds.
Conservation
In 2007, there were about 9 or 10 occurrences of the plant, with some occurrences made up of two or more small populations. The total population number varies year to year, generally because of the influence of local weather changes on the germinationGermination
Germination is the process in which a plant or fungus emerges from a seed or spore, respectively, and begins growth. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm. However the growth of a sporeling from a spore, for example the...
of seeds and the growth of seedling
Seedling
thumb|Monocot and dicot seedlingsA seedling is a young plant sporophyte developing out of a plant embryo from a seed. Seedling development starts with germination of the seed. A typical young seedling consists of three main parts: the radicle , the hypocotyl , and the cotyledons...
s. Past total population estimates varied from 1680 to nearly 3000 individuals. Some populations are located on private land and have not been surveyed in many years. Others are quite variable in size, increasing from 58 to 770 individuals, or decreasing from hundreds of plants to only 3.
A major threat to this species is habitat fragmentation
Habitat fragmentation
Habitat fragmentation as the name implies, describes the emergence of discontinuities in an organism's preferred environment , causing population fragmentation...
; populations have been bisected by road
Road
A road is a thoroughfare, route, or way on land between two places, which typically has been paved or otherwise improved to allow travel by some conveyance, including a horse, cart, or motor vehicle. Roads consist of one, or sometimes two, roadways each with one or more lanes and also any...
s, dirtbike trails, and firebreak
Firebreak
A firebreak is a gap in vegetation or other combustible material that acts as a barrier to slow or stop the progress of a bushfire or wildfire. A firebreak may occur naturally where there is a lack of vegetation or "fuel", such as a river, lake or canyon...
s. At least two populations are in the middle of residential subdivisions
Subdivision (land)
Subdivision is the act of dividing land into pieces that are easier to sell or otherwise develop, usually via a plat. The former single piece as a whole is then known in the United States as a subdivision...
, or on the edges; these may be extirpated
Local extinction
Local extinction, also known as extirpation, is the condition of a species which ceases to exist in the chosen geographic area of study, though it still exists elsewhere...
by now. Residential and commercial development continue to claim the habitat, as does the expansion of infrastructure
Infrastructure
Infrastructure is basic physical and organizational structures needed for the operation of a society or enterprise, or the services and facilities necessary for an economy to function...
to support the new development, including local services, utilities
Public utility
A public utility is an organization that maintains the infrastructure for a public service . Public utilities are subject to forms of public control and regulation ranging from local community-based groups to state-wide government monopolies...
, and roads. Livestock
Livestock
Livestock refers to one or more domesticated animals raised in an agricultural setting to produce commodities such as food, fiber and labor. The term "livestock" as used in this article does not include poultry or farmed fish; however the inclusion of these, especially poultry, within the meaning...
are allowed to graze
Grazing
Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
in some areas, but it is unknown if this affects the species. Since most of the populations are small, they are vulnerable to destruction from any one severe local event, such as drought
Drought
A drought is an extended period of months or years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region...
or disease, and since the populations sometimes fall to very low numbers they are at risk for genetic bottlenecks
Population bottleneck
A population bottleneck is an evolutionary event in which a significant percentage of a population or species is killed or otherwise prevented from reproducing....
and genetic drift
Genetic drift
Genetic drift or allelic drift is the change in the frequency of a gene variant in a population due to random sampling.The alleles in the offspring are a sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces...
.