When I see the word "rollers" the first thing that comes to my mind is bicycle rollers used off season for indoor practice; secondly I would think of the old hair rollers; third would be a rolling pin to roll out pie crust or cookie dough. I would never have thought of a plant of any kind.
Sure, I could look this up and have the Google explain it but will get better answers if I post it as an "Ask A Question for the experienced plant people to explain:
Why are some Sempervivum called "Rollers" or "Roller"? This inquiring mind wants to know.
