''Homalocephala polycephala'',

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

''Echinocactus polycephalus'', is a

cactus A cactus (: cacti, cactuses, or less commonly, cactus) is a member of the plant family Cactaceae (), a family of the order Caryophyllales comprising about 127 genera with some 1,750 known species. The word ''cactus'' derives, through Latin, ...

that is native to the United States and Mexico. It occurs in the

Mojave Desert The Mojave Desert (; ; ) is a desert in the rain shadow of the southern Sierra Nevada mountains and Transverse Ranges in the Southwestern United States. Named for the Indigenous peoples of the Americas, indigenous Mohave people, it is located pr ...

region of

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

, and

Nevada Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...

, and also occurs in the

Sonoran Desert The Sonoran Desert () is a hot desert and ecoregion in North America that covers the northwestern Mexican states of Sonora, Baja California, and Baja California Sur, as well as part of the Southwestern United States (in Arizona and California). It ...

region of southern

and northern

Sonora Sonora (), officially Estado Libre y Soberano de Sonora (), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is divided into Municipalities of Sonora, 72 ...

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

. The plants grow in some of the most extreme arid environments in the American Southwest, such as

Death Valley National Park Death Valley National Park is a national park of the United States that straddles the California–Nevada border, east of the Sierra Nevada. The park boundaries include Death Valley, the northern section of Panamint Valley, the southern sect ...

, and the

Mojave National Preserve Mojave National Preserve is a United States National Preserve located in the Mojave Desert of San Bernardino County, California, US, between Interstate 15 in California, Interstate 15 and Interstate 40. The preserve was established October 31, ...

Southern California Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural List of regions of California, region that generally comprises the southern portion of the U.S. state of California. Its densely populated coastal reg ...

Description

The stems of ''Homalocephala polycephala'' are sometimes solitary, but more often in clusters of as many as 30, each up to 0.6 m tall. The spines are yellow to red. The fruits are densely woolly, giving the common name cotton top cactus. The tendency of the cactus to cluster causes it to also be called many-headed barrel cactus.UC/JEPS: Jepson Manual treatment for ECHINOCACTUS polycephalus var. polycephalus
/ref> They have a reputation for being difficult in cultivation, and are rarely seen in cactus collections.

References

{{Taxonbar, from1=Q62084197, from2=Q310105, from3=Q109405330 Cactoideae Cacti of Mexico Cacti of the United States Flora of Arizona Flora of California Flora of Nevada Flora of Sonora North American desert flora Flora of the California desert regions Flora of the Sonoran Deserts Natural history of the Colorado Desert Natural history of the Mojave Desert ~ Mojave National Preserve Plants described in 1856