Coryphantha radians Bernal, Qro, MEX

|3,5-5 cm Ø|Great similarity with Coryphantha cornifera. Coryphantha cornifera is thought to be the taxon classified as Mammillaria radians by de Candolle in 1828, but this is unclear, partly because of various name changes over the years. However, the range of Coryphantha radians and Coryphantha cornifera is identical, and in most locations adult plants can be found either without central spines (radians) or with 1-4 central spines (cornifera). The arrangement of the central spines is variable. With the exception of the absence or presence of central spines, all other characteristics are absolutely identical, namely size and shape of the tubercles, number, size and arrangement of the marginal spines, flowers, fruits and seeds. In addition, this species belongs to the coryphanthes that go through a purely radially spined long juvenile stage in which they are already capable of flowering. Most plants develop the central spines after a few years, which give the plant the appearance of a sea urchin.[syn. Coryphantha cornifera]

hints on cultivation:
from warm veld, sunny and warm, do not like wet conditions,at least 5 °C during dry rest season