Pediocactus bradyi
Encyclopedia
Pediocactus bradyi is a rare species of cactus
known by the common names Brady's pincushion cactus, Brady's hedgehog cactus, and Marble Canyon cactus. It is endemic to Arizona
in the United States, where it is known only from Marble Canyon
in Coconino County
. It is limited to a specific type of soil
, it has a small distribution, and the species is threatened by a number of human activities. This has been a federally listed endangered species
of the United States since 1979.
This cactus is globose, tubercular, and usually solitary. It is up to about 6 centimeters tall by 5 wide. Each areole
has some wool and several slightly curved yellowish to white spines up to half a centimeter long. There are occasionally one or two central spines which are darker in color. The cactus flowers in the early spring. The flower is up to roughly 2 centimeters long by 3 wide and has red or green-striped yellowish outer tepal
s and straw-colored inner tepals. The fruit is green ripening red-brown and about a centimeter long. The cactus shrinks and retracts under the ground during the dry season, making it very hard to find. The related cacti Pediocactus winkleri
and Pediocactus despainii
are sometimes included as subspecies of P. bradyi.
The cactus grows on sandstone
and shale
land originating from the Moenkopi Formation
, a geologic formation
. This rock is covered in chips and gravel of Kaibab limestone
, forming the plant's substrate. It is not found in any other soil types. It grows alongside plants such as shadscale
(Atriplex confertifolia), snakeweed
(Gutierrezia sarothrae), and Mormon tea
(Ephedra viridis).
This plant was listed as an endangered species because of many threats, including highway construction and maintenance, off-road vehicle
use, cattle grazing, and poaching
. Natural threats to the species include frost heaving
. The small population size limited in distribution makes it vulnerable to extinction
.
Cactus
A cactus is a member of the plant family Cactaceae. Their distinctive appearance is a result of adaptations to conserve water in dry and/or hot environments. In most species, the stem has evolved to become photosynthetic and succulent, while the leaves have evolved into spines...
known by the common names Brady's pincushion cactus, Brady's hedgehog cactus, and Marble Canyon cactus. It is endemic to Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
in the United States, where it is known only from Marble Canyon
Marble Canyon
Marble Canyon is the section of the Colorado River canyon in northern Arizona from Lee's Ferry to the confluence with the Little Colorado River, which marks the beginning of the Grand Canyon....
in Coconino County
Coconino County, Arizona
-2010:Whereas according to the 2010 U.S. Census Bureau:*61.7% White*1.2% Black*27.3% Native American*1.4% Asian*0.1% Native Hawaiian or Pacific Islander*3.1% Two or more races*5.2% Other races*13.5% Hispanic or Latino -2000:...
. It is limited to a specific type of soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
, it has a small distribution, and the species is threatened by a number of human activities. This has been 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...
of the United States since 1979.
This cactus is globose, tubercular, and usually solitary. It is up to about 6 centimeters tall by 5 wide. Each areole
Areole
Areoles are an important diagnostic feature of cacti, and identify them as a family distinct from other succulent plants. The areoles on cacti are clearly visible; they generally appear as small light- to dark-colored bumps, out of which grow clusters of spines...
has some wool and several slightly curved yellowish to white spines up to half a centimeter long. There are occasionally one or two central spines which are darker in color. The cactus flowers in the early spring. The flower is up to roughly 2 centimeters long by 3 wide and has red or green-striped yellowish outer tepal
Tepal
Tepals are elements of the perianth, or outer part of a flower, which include the petals or sepals. The term tepal is more often applied specifically when all segments of the perianth are of similar shape and color, or undifferentiated, which is called perigone...
s and straw-colored inner tepals. The fruit is green ripening red-brown and about a centimeter long. The cactus shrinks and retracts under the ground during the dry season, making it very hard to find. The related cacti Pediocactus winkleri
Pediocactus winkleri
Pediocactus winkleri, commonly known as Winkler's cactus or Winkler's pincushion cactus, is a small cactus found only in Emery County, Utah or Wayne County, Utah in eastern Utah....
and Pediocactus despainii
Pediocactus despainii
Pediocactus despainii is a rare species of cactus known by the common names Despain's pincushion cactus, Despain footcactus, and San Rafael cactus. It is endemic to the state of Utah in the United States, where it is limited to the San Rafael Swell in Emery County. There are two populations...
are sometimes included as subspecies of P. bradyi.
The cactus grows on sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
and shale
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
land originating from the Moenkopi Formation
Moenkopi Formation
The Moenkopi is a geological formation that is spread across the U.S. states of New Mexico, northern Arizona, Nevada, southeastern California, eastern Utah and western Colorado. This unit is considered to be a group in Arizona. Part of the Colorado Plateau and Basin and Range, this formation was...
, a geologic formation
Geologic formation
A formation or geological formation is the fundamental unit of lithostratigraphy. A formation consists of a certain number of rock strata that have a comparable lithology, facies or other similar properties...
. This rock is covered in chips and gravel of Kaibab limestone
Kaibab Limestone
The Kaibab is a geologic formation that is spread across the U.S. states of northern Arizona, southern Utah, east central Nevada and southeast California. This geologic unit is part of the Park City Group in Nevada and Utah and is sometimes locally classified as a geologic group in Utah...
, forming the plant's substrate. It is not found in any other soil types. It grows alongside plants such as shadscale
Atriplex confertifolia
Atriplex confertifolia is a species of evergreen shrub in the Chenopodiaceae family, which is native to the western United States.-Habitat:Shadscale is a common, often dominant, shrub in the lowest and driest areas of the Great Basin...
(Atriplex confertifolia), snakeweed
Gutierrezia sarothrae
Gutierrezia sarothrae is a species of flowering plant in the daisy family known by the common names broom snakeweed and perennial matchweed. It is native to much of the western half of North America, from central Canada to northern Mexico...
(Gutierrezia sarothrae), and Mormon tea
Ephedra viridis
Ephedra viridis is a species of Ephedra known by the common names green ephedra and green Mormon tea. It is native to the western United States, where it is a member of varied scrub, woodland, and open habitats.-Description:...
(Ephedra viridis).
This plant was listed as an endangered species because of many threats, including highway construction and maintenance, off-road vehicle
Off-road vehicle
An off-road vehicle is considered to be any type of vehicle which is capable of driving on and off paved or gravel surface. It is generally characterized by having large tires with deep, open treads, a flexible suspension, or even caterpillar tracks...
use, cattle grazing, and poaching
Poaching
Poaching is the illegal taking of wild plants or animals contrary to local and international conservation and wildlife management laws. Violations of hunting laws and regulations are normally punishable by law and, collectively, such violations are known as poaching.It may be illegal and in...
. Natural threats to the species include frost heaving
Frost heaving
Frost heaving results from ice forming beneath the surface of soil during freezing conditions in the atmosphere. The ice grows in the direction of heat loss , starting at the freezing front or boundary in the soil...
. The small population size limited in distribution makes it vulnerable to extinction
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
.