And those spines are soft and britttle,like chalk.

Arizona Snowcap mammilaria
Moderators: rjlittlefield, ChrisR, Chris S., Pau
Oh yea i do go to the BCSS site a bit, had a few plants(including that one) from members on there,good kind folkDaveW wrote:Yes, if you follow David Hunt's nomenclature it is a Mamm vetula subspecies. Botany now seems to be following Zoology in using subspecies at infraspecific rank instead of variety as used to be the case.
As the origins of the plant are not generally known, and as it has received the cultivar name 'Arizona Snowcap', it is either likely to be a sport or a selected clone that is probably not known in the wild. With a name like 'Arizona Smowcap' it obviously arose in the US.
I still tend to use the shorthand Mamm gracilis having been a collector for 45 years, so my first real cactus book was Borg's Cacti in the 1960's and his nomenclature tends to stick as a form of shorthand! I presume therefore you are a collector and a member of the BCSS too?
David Whiteley (AKA DaveW)
Member:- British Cactus & Succulent Society, Cactus & Succulent Society of America, Mammillaria Society, Tephrocactus Study Group and a founder member of The Chileans