# Mountain Ball Cactus (*pediocactus simpsonii*) The Mountain Ball Cactus (Pediocactus simpsonii) is a hardy and charming succulent native to the high-elevation regions of western North America. Residing at altitudes of up to 10,000 feet, this resilient little plant is famous for its incredible cold tolerance, braving freezing winter temperatures that would easily kill most other cacti. Growing as a solitary or small-clumped sphere, it acts as a vital component of the alpine and subalpine ecosystems it calls home. During the late spring and early summer, the Mountain Ball Cactus transforms from an unassuming, spiky mound into a breathtaking display of color. It produces a crown of delicate pink, yellow, or white blossoms at its apex, attracting native bumblebees and other pollinators. Because of its adaptability and compact size, it has earned a special place in the hearts of desert-plant enthusiasts and hikers alike, who delight in spotting its vibrant blooms against the rugged, rocky terrain. - **Category:** [Plants](https://www.snappit.app/explore/categories/plant) - **Rarity:** Common - **Danger:** 1/5 · Very low - **Snaps:** 1 - **Habitat:** Typically found in rocky, well-drained soils within high-altitude grasslands, sagebrush scrub, and open pine woodlands of the western United States. ![Mountain Ball Cactus](https://inaturalist-open-data.s3.amazonaws.com/photos/6996990/medium.jpg) Photo: Robbie Hannawacker, CC0 · [iNaturalist](https://www.inaturalist.org/photos/6996990) ## Appearance This small cactus features a globular to egg-shaped stem that typically measures 3 to 15 centimeters in height and diameter. It is densely covered in clusters of straight, needle-like spines radiating outward, ranging in color from white and yellow to reddish-brown, which almost completely obscure the green flesh underneath. In spring, a tight cluster of bell-shaped flowers emerges from the top center of the plant, showing shades of pink, magenta, white, or pale yellow, which are later replaced by small, dry, green to reddish seed pods. ## Taxonomy - **Kingdom:** Plantae - **Phylum:** Tracheophyta - **Class:** Magnoliopsida - **Order:** Caryophyllales - **Family:** Cactaceae - **Genus:** Pediocactus ## Interesting facts - During the freezing winter months, the cactus can lose so much water that it shrivels and pulls itself partially flat or even slightly underground to escape freezing alpine winds. - It is one of the most northerly and highest-altitude occurring cacti in North America, thriving at elevations up to 3,000 meters. - The species name 'simpsonii' honors James H. Simpson, a 19th-century US Army engineer who collected specimens during his western expeditions. ## Special abilities - **Cryo Dehydration:** To survive sub-zero alpine winters, the cactus expels water from its cells into extracellular spaces, preventing destructive ice crystal formation within its vital tissues. - **UV Blocking Spines:** A dense mesh of overlapping spines acts as natural sunscreen, shading the stem from intense high-altitude ultraviolet radiation and reducing desiccating wind exposure. - **CAM Photosynthesis:** It utilizes Crassulacean Acid Metabolism, opening its stomata exclusively at night to absorb carbon dioxide, dramatically reducing daytime water loss in dry climates. ## Measurements & details - **Length:** 3-15 cm - **Weight:** 0.05-0.8 kg - **Lifespan:** 15-50 years ## Diet & Feeding As a photosynthetic plant, the Mountain Ball Cactus produces its own chemical energy from sunlight, carbon dioxide, and water, supplemented by minerals absorbed through its shallow root system. - **Primary Foods:** Sunlight, Carbon dioxide, Water, Soil minerals ## Ecological connections - **Mutualism:** Hunt's Bumblebee (*Bombus huntii*) — Provides essential nectar and pollen during the spring, relying on the insects for cross-pollination. - **Mutualism:** [Western Harvester Ant](https://www.snappit.app/explore/western-harvester-ant) (*Pogonomyrmex occidentalis*) — Collects the small seeds, feeding on some while dispersing and planting others in nutrient-rich nest debris. ## Safety **Danger:** 1/5 · Very low No special safety notes yet. ## Frequently Asked Questions ### How to identify Mountain Ball Cactus? Compare leaf arrangement, rosette shape, ribs, spines and flowers. Keep in mind that drought and strong sun can shift a plant's color and shape. Succulent Identifier: upload a photo and compare the visible details. ### How long is Mountain Ball Cactus? 3-15 cm ### How much does Mountain Ball Cactus weigh? 0.05-0.8 kg ### How long does Mountain Ball Cactus live? 15-50 years ### What does Mountain Ball Cactus eat? As a photosynthetic plant, the Mountain Ball Cactus produces its own chemical energy from sunlight, carbon dioxide, and water, supplemented by minerals absorbed through its shallow root system. ### Where is Mountain Ball Cactus usually found? Typically found in rocky, well-drained soils within high-altitude grasslands, sagebrush scrub, and open pine woodlands of the western United States. ## Where to spot - [Dinosaur Ridge](https://www.snappit.app/guides/places/dinosaur-ridge) — Colorado, US · Natural Landmark - [Gold Hill](https://www.snappit.app/guides/places/gold-hill) — Colorado, US · Neighborhood - [Rocky Mountain National Park Utility Area Historic District](https://www.snappit.app/guides/places/rocky-mountain-national-park-utility-area-historic-district) — Colorado, US · Historic District - [Shawnee](https://www.snappit.app/guides/places/shawnee) — Colorado, US · Neighborhood [View all places to see Mountain Ball Cactus](https://www.snappit.app/guides/where-to-see/mountain-ball-cactus) ## More Plants - [white snakeroot](https://www.snappit.app/explore/white-snakeroot) (*Ageratina altissima*) - [tree-of-heaven](https://www.snappit.app/explore/tree-of-heaven) (*Ailanthus altissima*) - [western sword fern](https://www.snappit.app/explore/western-sword-fern) (*Polystichum munitum*) - [common milkweed](https://www.snappit.app/explore/common-milkweed) (*Asclepias syriaca*) --- Source: [Mountain Ball Cactus: Facts & Places to See — Snappit](https://www.snappit.app/explore/mountain-ball-cactus)