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General: Cottontop Cactus (Echinocactus polycephalus) looks like a cross between a
Hedgehog Cactus and a Barrel Cactus. Individual
stems look like barrel cactus, but they grow in clumps like hedgehogs. The stems grow to about 12-inches in diameter and about
15-inches tall, and they have ribs (flutes) running from bottom to top. The stems are loosely covered with relatively long, stout,
flattened spines like those on barrel cactus. Flowers grow from the top of the stems, and the fruits are covered in soft, woolly
spines. Clumps grow to about 3-ft in diameter and height.
Cottontop Cactus are generally uncommon, but they can be locally common components of the desert vegetation community. Cottontops occur
in the Upper Sonoran Life Zone (Mojave Desert Scrub). A good place to see this species is along
the Mormon Well Road in the Desert National Wildlife Range, a few miles east of Corn Creek Station. |
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Family: Cactus (Cactaceae).
Other Names: woolly cactus, woolly-headed cactus, many-headed barrel cactus.
Plant Form: Clumps of upright, short, globular stems that emerge from the ground. Stems ribbed, with spines growing
from the top of the ridges.
Height: Stems 12- to 15-inches tall, 12-inches in diameter; clumps to 3-ft high and 3-ft wide.
Trunk: None. |
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Leaves: None (reduced to spines).
Flowers: Small, yellow; blooms in late spring to early summer.
Fruit: Oblong, 2.5-inches long, densely woolly.
Seeds: Black, 1/8-inch long.
Habitat: Rocky bajadas and outcrops. |
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Distribution: Found in southwestern Utah, southern Nevada, and northwestern
Arizona.
Elevation: 1,000 to 5,000 ft.
Comments: Desert birds use the cotton for nest-lining material.
This species can be told from California Barrel Cactus (Ferocactus cylindraceus)
by the presence or absence of wool. Cottontop Cactus have some wool on the top of the stem and on the fruits, while California
Barrel Cactus does not have wool. In addition, Cottontop Cactus form clumps, while barrel cactus tend to be solitary. |
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Typical specimen in typical habitat. |
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Sometimes the heads are well spread out. |
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Usually, the heads are tightly packed, however this specimen is unusually large. |
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Perhaps a young specimen with only a few heads. |
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Cottontop flower. |
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Cottontop flower. |
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Cottontop flower. |
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Cottontop flower. |
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Cottontop Cactus with fruits, which are covered in long hairs. |
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Cottontop Cactus with an unusual amount of hair on the fruits. |
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A single Cottontop Cactus fruit |
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Often times, the Cottontop Cactus fruits are held in place by the spines on the top of the cactus. |
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Birds and small mammals us the fluff on Cottontop Cactus fruits for nesting material. These fruits seem to have been pulled out by an animal. |