Coryphanthus echinus, photographed in Big Bend region, Texas
Coryphanthus echinus is a globular cactus that seldom offsets; it has bright yellow flowers. Some plants may have areoles with a porrect central spine, whereas other areoles lack such a spine. The plants are generally easy to grow and have a reputation of being cold hardy (to USDA climate zone 6).
You can read more about C. echinus here. You can purchase C. echinus from High Country Gardens.
written by: jshaw at opuntiads.com
In a Coryphantha family, only C. elephantidense is popular in Japan.
C. echinus has been hardly known. But now I recognize a charm of it.
I want to try to seed it.
i agree this species is not very often grown. have grown this for 4-5 years no with now problems such as rotting, winters outdoors against a south wall in a clay pot here in zone 7B no damage. is one of the better bloomers, flowers tend to open in a complete ring on top of plant. though they last only 1-2 days it blooms several times during mid-summer to early fall. highly recomended!