''Pediocactus bradyi'' is a very rare species of

cactus A cactus (, or less commonly, cactus) is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word ''cactus'' derives, through Latin, from the Ancient Gree ...

known by the common names Brady's pincushion cactus, Brady's hedgehog cactus, and Marble Canyon cactus. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

in the USA, where it is restricted to

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. Lee's Ferry is a common launching point for rive ...

Coconino County Coconino County is a county in the north-central part of the U.S. state of Arizona. Its population was 145,101 at the 2020 census. The county seat is Flagstaff. The county takes its name from ''Cohonino'', a name applied to the Havasupai p ...

, though its exact distribution is not generally advertised due to poaching concerns.''Pediocactus bradyi''.
The Nature Conservancy. It is limited to a specific type of

soil Soil, also commonly referred to as earth or dirt Dirt is an unclean matter, especially when in contact with a person's clothes, skin, or possessions. In such cases, they are said to become dirty. Common types of dirt include: * Debri ...

, 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.

Description

This cactus is globose, tubercular, and usually solitary. It is up to about 6 centimeters tall by 5 wide. Each

areole In botany, areoles are small light- to dark-colored bumps on cacti out of which grow clusters of spines. Areoles are important diagnostic features of cacti, and identify them as a family distinct from other succulent plants. Gordon Rowley - W ...

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 A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...

s and straw-colored inner tepals. The fruit is green ripening red-brown and about a centimeter long.''Pediocactus bradyi''.
Flora of North America. The cactus shrinks and retracts under the ground during the dry season, making it very hard to find.USFWS
Determination that ''Pediocactus bradyi'' is an Endangered Species.
''Federal Register'' October 26, 1979. The related cacti '' Pediocactus winkleri'' and ''

Pediocactus despainii ''Pediocactus despainii'' is a rare species of cactus known by the common names Despain's cactus 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, Utah.

'' are sometimes included as subspecies of ''P. bradyi''.

Subspecies

Distribution and habitat

The cactus grows on

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

and shale land originating from the

Moenkopi Formation The Moenkopi Formation 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 ...

, a

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

. This rock is covered in chips and gravel of

Kaibab limestone The Kaibab Limestone is a resistant cliff-former, cliff-forming, Permian geologic formation that crops out across the U.S. states of northern Arizona, southern Utah, east central Nevada and southeast California. It is also known as the Kaibab Fo ...

, forming the plant's substrate. It is not found in any other soil types. It grows alongside plants such as

shadscale ''Atriplex confertifolia'', the shadscale or spiny saltbush, is a species of evergreen shrub in the family Amaranthaceae, which is native to the western United States and northern Mexico Mexico (Spanish: México), officially the United Me ...

(''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 An off-road vehicle, sometimes referred to as an overland or adventure 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 de ...

use, cattle grazing, and

poaching Poaching has been defined as the illegal hunting or capturing of wild animals, usually associated with land use rights. Poaching was once performed by impoverished peasants for subsistence purposes and to supplement meager diets. It was set a ...

. Natural threats to the species include

frost heaving Frost heaving (or a frost heave) is an upwards swelling of soil during freezing conditions caused by an increasing presence of ice as it grows towards the surface, upwards from the depth in the soil where freezing temperatures have penetrated in ...

. The small population size limited in distribution makes it vulnerable to

extinction Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually 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 ...

. It is also vulnerable to the effects of climate change, especially increased droughts.

References

External links

USDA Plants Profile for ''Pediocactus bradyi''UC Photos gallery − ''Pediocactus bradyi''
{{Taxonbar, from=Q150219 Cacti of the United States Flora of Arizona Endemic flora of the United States Natural history of Coconino County, Arizona Natural history of the Grand Canyon Critically endangered flora of the United States bradyi