The bright red, funnelform flowers of this species are so distinctive that Britton & Rose put it in its own genus Mammillopsis. The flowers are large (to 7 cm long and 6 cm diameter) and, therefore, are not produced in the crowning profusion of smaller flowered species. Nevertheless, even a single flower is a sight to behold. The red color is attractive to hummingbird pollinators and stands out against the snowy white spines. The Velcro-like, hooked central spines make this a challenging plant to repot but it is worth it to encourage flowering and the clustering potential of the species that can create clumps of dozens of stems. It grows natively in the mountains of northwestern Mexico at elevations from 2400 to 2800 m where it can be found growing among pine needles and periodically dusted with snow. HBG 59492, seed-grown, tennis-ball-sized plants, $7.