Echinocactus horizonthalonius
Encyclopedia
Echinocactus horizonthalonius is a species of cactus
known by several common names, including devilshead, turk's head cactus, blue barrel cactus, eagle's claw, horse maimer, and visnaga meloncillo. It is native to the southwestern United States and northern Mexico, where it occurs in desert habitat, particularly on limestone
substrates.
This cactus is gray-green to blue-gray in color and spherical, hemispherical, columnar, or flat-topped in shape. It reaches a maximum size of about 45 centimeters tall by 20 wide. The body is made up of curving sections that twist around the body in a helical
fashion. These sections are lined with areole
s bearing up to 10 spines each. The pink, gray, or brown spines may be over 4 centimeters long. The bright pink to magenta
flowers are up to 7 to 9 centimeters wide. Flowers open around midday and close for the night. They also open after the plant receives rainfall, and although most of the flowers occur in June, they may bloom again in late summer and fall if rain occurs. The fruit is hairy or woolly and pink or red in color.
The species is generally divided into two varieties. The more common, var. horizonthalonius, can be found from Arizona
to Texas
and into Mexico. The rare var. nicholii (Nichol's turk's head cactus) is known only from three populations in southeastern Arizona and one in Sonora
, Mexico. It is federally listed as an endangered species
of the United States. Some populations are protected within Ironwood Forest National Monument
in Pinal
and Pima Counties
in Arizona.
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 several common names, including devilshead, turk's head cactus, blue barrel cactus, eagle's claw, horse maimer, and visnaga meloncillo. It is native to the southwestern United States and northern Mexico, where it occurs in desert habitat, particularly on limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
substrates.
This cactus is gray-green to blue-gray in color and spherical, hemispherical, columnar, or flat-topped in shape. It reaches a maximum size of about 45 centimeters tall by 20 wide. The body is made up of curving sections that twist around the body in a helical
Helix
A helix is a type of smooth space curve, i.e. a curve in three-dimensional space. It has the property that the tangent line at any point makes a constant angle with a fixed line called the axis. Examples of helixes are coil springs and the handrails of spiral staircases. A "filled-in" helix – for...
fashion. These sections are lined with 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...
s bearing up to 10 spines each. The pink, gray, or brown spines may be over 4 centimeters long. The bright pink to magenta
Magenta
Magenta is a color evoked by light stronger in blue and red wavelengths than in yellowish-green wavelengths . In light experiments, magenta can be produced by removing the lime-green wavelengths from white light...
flowers are up to 7 to 9 centimeters wide. Flowers open around midday and close for the night. They also open after the plant receives rainfall, and although most of the flowers occur in June, they may bloom again in late summer and fall if rain occurs. The fruit is hairy or woolly and pink or red in color.
The species is generally divided into two varieties. The more common, var. horizonthalonius, can be found from 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...
to Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
and into Mexico. The rare var. nicholii (Nichol's turk's head cactus) is known only from three populations in southeastern Arizona and one in Sonora
Sonora
Sonora officially Estado Libre y Soberano de Sonora is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided into 72 municipalities; the capital city is Hermosillo....
, Mexico. It is federally listed as an 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. Some populations are protected within Ironwood Forest National Monument
Ironwood Forest National Monument
Ironwood Forest National Monument is located in the Sonoran Desert and the U.S. state of Arizona. Created by Bill Clinton by Presidential Proclamation 7320 on June 9, 2000, the 129,022 acre monument is managed by the U.S. Bureau of Land Management, an agency within the U.S. Department of the...
in Pinal
Pinal County, Arizona
-2010:Whereas according to the 2010 U.S. Census Bureau:*72.4% White*4.6% Black*5.6% Native American*1.7% Asian*0.4% Native Hawaiian or Pacific Islander*3.8% Two or more races*11.5% Other races*28.5% Hispanic or Latino -2000:...
and Pima Counties
Pima County, Arizona
-2010:Whereas according to the 2010 U.S. Census Bureau:*74.3% White*3.5% Black*3.3% Native American*2.6% Asian*0.2% Native Hawaiian or Pacific Islander*3.7% Two or more races*12.4% Other races*34.6% Hispanic or Latino -2000:...
in Arizona.
External links
- Echinocactus horizonthalonius. The Nature Conservancy.
- Echinocactus horizonthalonius. Center for Plant Conservation
- Photo gallery