Cottontop Cactus
ExplorePlants
Cottontop Cactus
homalocephala polycephala
The Cottontop Cactus (Homalocephala polycephala) is a striking, multi-headed barrel cactus native to the extremely arid deserts of the American Southwest. Easily recognized by its dense, protective canopy of thick, overlapping spines and white woolly crowns, this resilient plant thrives in some of the harshest, driest environments on Earth. It often forms dense clumps or mounds containing up to a hundred individual stems, creating a dramatic, fortress-like appearance on rocky desert hillsides. As a slow-growing survivor, it plays a vital role in its desert ecosystem, providing nesting shelter and nourishment for local wildlife. During late spring, its woolly tops burst into vibrant yellow flowers with red centers, contrasting beautifully against its formidable, interlocking armor.
Habitat: Found on extremely dry, rocky slopes, gravelly alluvial fans, and canyon walls within the Mojave and Sonoran Deserts.
Appearance
This cactus grows in clustered mounds of globose to cylindrical stems, with individual stems reaching up to 60 centimeters in height. The stems are heavily guarded by thick, heavily ringed, reddish-grey to straw-colored spines that flatten and curve slightly. The most distinctive feature is the dense white wool that covers the growing tip of each stem, from which small, yellow, funnel-shaped flowers emerge.
KingdomPlantaePhylumTracheophytaClassMagnoliopsidaOrderCaryophyllalesFamilyCactaceaeGenusHomalocephala
Category
PlantsRarity
Common
Danger
1/5 · Very low
Snaps
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Interesting facts
A single massive cluster of Cottontop Cactus can contain over a hundred individual heads and take more than a century to grow to full size.
Its heavily ringed, rigid spines are so tough and sharp that they can easily puncture standard vehicle tires.
The dense, woolly fibers at the top of the cactus were historically used by Native Americans as a soft filling material and for starting fires.
Special abilities
Ability
Woolly Apex Protection
The dense white wool at the crown insulates delicate growing tissues from extreme solar radiation and freezing night temperatures.
Ability
Fortress Clumping
It grows in tight, multi-headed mounds that reduce wind exposure, collect water efficiently, and deter large herbivores with a dense grid of overlapping spines.
Ability
CAM Photosynthesis
Like many desert plants, it opens its stomata at night to absorb carbon dioxide, dramatically reducing water loss during the scorching desert day.
Measurements & details
- Length
- 10-60 cm
- Weight
- 5-150 kg
- Lifespan
- 50-150 years
Diet & Feeding
As a photosynthetic plant, it produces its own energy using sunlight, water, and carbon dioxide.
Primary Foods
- Sunlight
- Carbon dioxide
- Water
- Soil minerals
Ecological connections
eaten by
Desert Woodrat
Neotoma lepida
Chews on the fleshy stems of the cactus to obtain moisture and nutrients in the desert.
mutualism
Cactus Wren
Campylorhynchus brunneicapillus
Builds nests deep within the protective, spiny branches to shield nestlings from predators.
Traits
No trait badges are assigned for this object yet.
Also known as
No aliases listed yet.
Collections
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Safety
Danger
1/5 · Very low
No special safety notes yet.
Frequently Asked Questions
How to identify Cottontop Cactus?
The easiest way to identify Cottontop Cactus is to use the Snappit nature identifier app.
How long is Cottontop Cactus?
10-60 cm
How much does Cottontop Cactus weigh?
5-150 kg
How long does Cottontop Cactus live?
50-150 years
What does Cottontop Cactus eat?
As a photosynthetic plant, it produces its own energy using sunlight, water, and carbon dioxide.
Where is Cottontop Cactus usually found?
Found on extremely dry, rocky slopes, gravelly alluvial fans, and canyon walls within the Mojave and Sonoran Deserts.
Snap Map
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Recent Snaps
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Where to spot
Park15 sightings12 species
California, US
Calico Early Man Site
You might spot Creosote Bush, Desert Holly, and Cottontop Cactus.
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Park10 sightings12 species
California, US
Rodman Mountains
You might spot Frémont's Phacelia and Devil's Spineflower.
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Park11 sightings12 species
California, US
Skidoo
You might spot Desert Paintbrush and Desert Milkweed.
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