Once known as the relatively easy remember Mammillaria celsiana, this alternative name, from the 19th century, is for a mostly solitary species that divaricately branches. It forms rather tall (for a Mammillaria) plants with an overall pinkish gray appearance. The flowers are tiny and red. This species is hardy outdoors in Tucson. These are large plants that may call for exact shipping charges. These plants are seedlings in 6-inch pots.