General: Hairspine Cactus (Opuntia polyacantha var. polyacantha) is a low-growing cactus with broad, thin stem segments (pads). The pads are medium-sized for a pricklypear (to about 5-inches long by 3-inches wide). The spines are clustered, long (to about 3 inches), and straight. Often there are no spines at the base of the pad. Flowers can be yellow or rose-pink.

Hairspine Cactus is a locally common (uncommon overall, but can be abundant in certain areas) component of vegetation communities on well-drained sandy, gravelly, and rocky soils along washes, canyons, and on upper bajadas and moderate slopes into the lower mountains in the Upper Sonoran (Mojave Desert Scrub and Pinyon-Juniper Woodland), Transition (Yellow Pine), and Canadian (Pine-Fir Forest) life zones.

Around Las Vegas, this cactus is found at middle elevations in the mountains, making it difficult to find without a hike. A few can be found near Willow Springs at Red Rock Canyon NCA (Petroglyph Wall Trail).

Family: Cactus (Cactaceae).

Other Names: Plains Pricklypear, Opuntia polyacantha.

Plant Form: Upright shrub spreading from the ground.

Height: To about 18-inches tall.

Trunk: None.

Stems: Divided into segments; flat and broad (pancake shaped). To about 8-inches long and 5-inches wide.

Stem Surface: Smooth.

Spines: Spines 4 to 24 per areole, in all areoles; to about 3-inches long (variable).

Glochids: Present.

Flowers: Blooms late spring and early summer. Inflorescence: Solitary from upper edge of pads. Flower: yellow to magenta, about 2-inches diameter; filaments white, style white, stigma green.

Fruit: Spiny.

Seeds:

Habitat: Dry, well-drained sandy, gravelly, and rocky soils on upper bajadas and moderate slopes in the mountains.

Distribution: Central and western North America.

Elevation: 3,000 to 7,000 feet.

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