WILDFLOWERS OF NEW MEXICO
This low-spreading cactus to 10-inches high has prostrate, one-pad-high branches of flat, oval pads that often root in loose sand. Pads have diagonal rows of 4–14 woolly-tan areoles at midstem. Areoles bear clusters of stout to bristly or hair-like spines, yellow, brown, black, to whitish-gray. Note the fruit has both glochids and spines and dries tan-papery, not red-fleshy. The scientific name polyacanta, means “many spines.”
SPINES: Spines can occur on all areoles, or only on the upper ones, in either of two different arrays: var. hystricina has 7–18 spines, all similar but grading in length, dark brown to gray, longest 2–3 1/8 inches long (5–8 cm), spreading and curling in all directions; var. polyacantha has 1–3 major spines, yellow to brown to gray, 3/4–1 1/2-inches long (2–4 cm), and 1–3 minor spines, white to gray, downward-pointing, 3/16–3/8-inch long (5–10 mm). Tiny barbed, hair-like glochid bristles in the areoles cause painful irritation if touched.
FLOWER: April–May. Showy flowers to 3 1/2-inches wide (9 cm) have numerous solid-yellow (occasionally red) petal-like tepals; filaments white, yellow, to magenta, stigma has green lobes. Fruit matures to a dry, tan to brown cylinder 1/2–1 3/4-inches long (12–45 mm), armed with both glochids and numerous spines to 3/8-inch long (5–10 mm).
HABITAT: Sandy, gravelly soils, loose sand, decomposed granite, basalt rubble; desert scrub and grasslands, pinyon-juniper-oak woodlands.
ELEVATION: 3,800–8,200 feet.
RANGE: Widespread in variable forms in mosts states west of the Mississippi River.
SIMILAR SPECIES: Very limited in range and on the NM RARE Plant list, El Paso Prickly Pear, O. polyacantha var. arenaria (O. arenaria), in Dona Ana and Luna cos. in NM, and adjacent Tex., has flattened to egg-shaped pads to 3-inches long (8 cm) with spines in every areole and easily detached pads. Brittle Prickly Pear, O. fragilis, in the Four Corners, is mat-forming with 2-inch-thick cylindric to flattened pads that are easily detached, yellow flowers with red centers, and a dry, tan fruit with short spines.
NM COUNTIES: Nearly statewide (not reported in Roosevelt Co.) in low- to mid-elevation, arid habitats.
HAIR-SPINE (PLAINS) PRICKLY PEAR CACTUS
OPUNTIA POLYACANTHA
Cactus Family, Cactaceae
Perennial cactus
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Areoles on O. polyacantha var. polyacantha have 1–3 longer major spines, yellow to brown to gray, and 1–3 shorter minor spines, white to gray, downward-pointing
Yellow is the most common flower color, but either variety can have red flowers.
Areoles on Opuntia polyacantha var. hystricina have 7–18 spines, all similar but grading in length, dark brown to gray.
The fruit are tan and papery, not red and fleshy. Note the areoles have both spines and glochids.
Spines may cover pad or be only in the upper areoles.
Don’t try to touch the pads on the densely spiny Opuntia polyacantha var. hystricina
Opuntia polyacantha var. polyacantha has fewer spines per areole.
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