Bunched Cory Cactus

Coryphantha ramillosa is perhaps only a geographic race of the yellow-flowered C. delaetiana of northern Mexico. Coryphantha ramillosa differs from C. macromeris by several features: individual stems are more compact and rarely branched; areolar grooves (after sexual maturation) extend the full lengths of the tubercles; parenchyma is not slimy; and the pith is large and vascularized. The flowers are similar except for the long fringes on outer tepal margins of C. macromeris (entire in C. ramillosa and allied species).

Coryphantha ramillosa is in the Center for Plant Conservation’s National Collection of Endangered Plants.

Plants unbranched (rarely to 25 branches), loosely bristly or shaggy, with gray, brown, or whitish general aspect. Roots diffuse or strong taproots ¹/5 of stem diam. Stems deep-seated, aerial portion usually hemispheric or ± flat-topped, 0-9 × 4-9.5 cm; tubercles 8-20 × 6-9 mm, firm; areolar glands seasonally conspicuous; parenchyma not mucilaginous; pith ¹/2 of lesser stem diam.; medullary vascular system conspicuous. Spines 14-27 per areole, largest spinesterete, adaxial spines (both radial and subcentral) ± elongate, often twisted, flattened to angled; radial spines (9-)13-16(-20) per areole, white, 12-30 × 0.2-0.3 mm; subcentral spines often present, few per areole; outer central spines (2-)3(-5) per areole, either projecting conspicuously or erect and spreading in same plane as the radial spines, dull white to dark gray or reddish brown to dark brown, usually with dark brown to purplish black tips; inner central spine 1 per areole, ± porrect, straight or the largest spinesslightly curved, 22-43 × 0.5-0.7 mm. Flowers apical or nearly so, 38-65 × 30-50 mm; outer tepals entire; inner tepals pale pink to deep rose-purple, grading to white proximally, with darker midstripes, at least near tip, 17-25 × 3-4.5 mm; outer filaments white; anthers bright yellow to pale orange; stigma lobes 6-7, white, 3.5-7 mm. Fruits dark green to pale gray-green, obovoid, spheric, or ellipsoid, (10-)16-21(-25) × (10-)12-16 mm, succulent; floral remnant strongly persistent. Seeds yellow, drying to reddish brown, spheric to comma-shaped, keeled proximally, strophiole replaced by a linear raphe, 1-1.5 mm, finely and weakly raised-reticulate. 2n = 22.

Tex.; Mexico (Coahuila).

Flowering summer-early fall (Aug-Nov); fruiting Nov.

Chihuahuan desert scrub, limestone hills, ridges, benches; of conservation concern; 400-1000m.

Coryphantha ramillosa is a rare species of cactus known by the common names bunched cory cactus and whiskerbush. It is native to the border region between Texas in the United States and Coahuila in Mexico. Because it was believed to be rare and threatened by a number of processes, it was federally listed as a threatened species of the United States in 1979.

The range and abundance of this plant are not well known, especially within Mexico, and it may not be as uncommon as was thought in 1979. The cactus occurs in at least seven locations in Texas, several being within the bounds of Big Bend National Park. One of the most recent estimates of abundance in Texas is 5,000 to 10,000 individuals in two counties. The range of appropriate habitat in Mexico covers 2.5 times the amount of land as in Texas. Many of the plants are located in remote areas, which helps protect them from people. A major threat to the species is harvesting by cactus enthusiasts and dealers.

This cactus is generally spherical or cylindrical in shape, and unbranched. It grows up to about 9.5 centimeters long and is textured with protruding areoles up to 2 centimeters tall. The areoles bear curving spines, the central one thick, dark, and up to 4.3 centimeters in length. The smaller spines are light in color, often white. The showy flower occurs at the apex of the cactus body and measures up to 6.5 centimeters long. Its tepals are pink, lightening to pale pink or white near the center, and sometimes with darker mid-stripes. The rounded fruit is pale to dark green, fleshy and juicy and 1 or 2 centimeters long. The plant blooms in the summer, with an extended blooming period when rainfall is higher.

The cactus occurs in desert scrub habitat, generally in dry, rocky, barely accessible areas where few other plants grow. The substrate is limestone.

The plant is being propagated and studied at Desert Botanical Garden in Phoenix, Arizona.