''Pediocactus sileri'' is a 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 Siler's pincushion cactus and gypsum cactus (or gypsum plains cactus). It is native to southwestern
Utah
Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...
and northwestern
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 United States. 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 ...
, individuals are often spaced far apart, and the species is threatened by a number of human activities such as
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,
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 ...
, and
uranium
Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...
mining.
This is a federally listed threatened species of the United States.
Description
This cactus is egg-shaped or sometimes cylindrical in shape, and may have short branches. It is up to 25 centimeters tall by about 11 cm wide. The surface is bumpy with
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 ...
s which are covered in hairs or woolly fibers. Each areole has 3 to 7 main spines which are black to gray or white in color, those occurring near the base of the cactus body reaching up to 3 centimeters long. Each areole also has many smaller white spines 1 or 2 centimeters long. Spines around the base of the cactus may help to anchor it to the soil. The cactus flowers in April and May. The flower is up to 2 centimeters long by 3 cm wide and has white-margined brown 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 purple-veined yellow inner tepals. The fruit is yellow-green in color and just over a centimeter long.
[
]
Taxonomy
The names ''Pediocactus sileri'' and ''Sclerocactus sileri'' have a confused relationship in the literature. (''Pediocactus'' at one time included ''Sclerocactus
''Sclerocactus'' ("hard cactus", from Greek; refers to the hard, dry fruit) is a genus of cacti. It comprises about 15 species, the exact number depending on the authority. These species are very xerophytic. They are sometimes called 'fishhook ...
'', although they are now thought not to be closely related.)[, in ] According to the treatment in the ''Flora of North America'',[, in ] the taxon described here was first described as ''Echinocactus sileri'' in 1896 and transferred to ''Pediocactus sileri'' by L.D. Benson in 1961.[
* '']Sclerocactus sileri
''Sclerocactus sileri'', the Siler fishhook cactus, is a rare and very small cactus found mostly in mineral-rich desert areas of intermediate elevations, notably in the American states of Utah, Nevada, and northern Arizona.
Description
''Scler ...
'' (L.D. Benson) K.D. Heil & J M. Porter – Siler fishhook cactus[, in ]
Mistakenly, Anderson (2001) describes only one species, under the name ''Sclerocactus sileri'', treating ''Pediocactus sileri'' as a synonym.[, p. 629] His description largely matches the description of ''Pediocactus sileri'' in the ''Flora of North America'', and he uses the same common names (gypsum cactus, Siler's pincushion cactus) although the distribution he gives ("a very restricted area in Coconino County, Arizona") corresponds to that of ''Sclerocactus sileri'' in the ''Flora of North America'' ("restricted to northeast Coconino County, Arizona").[
]
Distribution and conservation
The cactus grows on sand and clay substrate that is part of 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 ...
, especially the Schnabkaib Member of the formation.[USFWS]
''Pediocactus sileri'' Five-year Review.
November 2008. The soils are rich in gypsum
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywal ...
and salts. Habitat in the area includes desert scrub
Deserts and xeric shrublands are a biome defined by the World Wide Fund for Nature. Deserts and xeric (ancient Greek xērós, “dry") shrublands form the largest terrestrial biome, covering 19% of Earth's land surface area. Ecoregions in this ...
, woodland
A woodland () is, in the broad sense, land covered with trees, or in a narrow sense, synonymous with wood (or in the U.S., the ''plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunlight and limited shade (se ...
s, and grassland
A grassland is an area where the vegetation is dominated by grasses ( Poaceae). However, sedge ( Cyperaceae) and rush ( Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur na ...
s.[ Most of the land is under the stewardship of the Bureau of Land Management.][ The plant's distribution covers parts of Coconino and Mohave Counties in Arizona and ]Washington
Washington commonly refers to:
* Washington (state), United States
* Washington, D.C., the capital of the United States
** A metonym for the federal government of the United States
** Washington metropolitan area, the metropolitan area centered o ...
and Kane Counties in Utah.[ Though the current total population of the cactus is unknown and has not been estimated, there have been over 10,000 individuals documented over a territory measuring just over .][
Threats to this species include uranium exploration. As the price of uranium has increased recently, mining claims have also increased in number.][ All occurrences of the cactus occur on land that has potential for uranium discovery. Plans for uranium mining have often been modified to avoid damage to the cactus, but the threat still exists. ]Petroleum exploration
Hydrocarbon exploration (or oil and gas exploration) is the search by petroleum geologists and geophysicists for deposits of hydrocarbons, particularly petroleum and natural gas, in the Earth using petroleum geology.
Exploration methods
Vis ...
and gypsum mining are considered future threats in the area, but not current ones. Off-road vehicles are popular in the local landscape, and there are designated roads for such activity and areas that are closed to vehicles for the protection of the plant. Grazing of livestock
Livestock are the domesticated animals raised in an agricultural setting to provide labor and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to animal ...
is considered a threat, but a minor one. Natural threats include drought
A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, an ...
and predation by rodents and rabbits.[
Conservation activities include the establishment of the White Dome Nature Preserve in Utah, which protects land that is home to the cactus, as well as to the rare dwarf bear claw poppy (''Arctomecon humilis'') and animals such as the zebra-tailed lizard ('']Callisaurus
The zebra-tailed lizard (''Callisaurus draconoides'') is a species of lizard in the family Phrynosomatidae. The species is native to the Southwestern United States and adjacent northwestern Mexico. There are nine recognized subspecies.
Habitat
...
draconoides'') and the loggerhead shrike
The loggerhead shrike (''Lanius ludovicianus'') is a passerine bird in the family Laniidae. It is the only member of the shrike family endemic to North America; the related northern shrike (''L. borealis'') occurs north of its range, however it ...
(''Lanius ludovicianus'').
References
External links
USDA Plants Profile for ''Pediocactus sileri''IUCN Red List.org: ''Pediocactus sileri'' (Siler's Pincushion Cactus)UC CalPhotos gallery of ''Pediocactus sileri''
{{Taxonbar, from=Q309833
Cacti of the United States
Flora of Arizona
Flora of Utah
Flora of the Colorado Plateau and Canyonlands region
Mohave County, Arizona
Natural history of Coconino County, Arizona
Endemic flora of the United States
Least concern flora of the United States
Taxa named by George Engelmann
sileri