Magnificent plant Alain. So, how old is your "oldest"? Fascinating how uniform the clump is; almost as though someone trimmed around the outer edge. I always have great appreciation of "older" plants, and those who can maintain them so well for so long. :)
More than 30 years old Bob. I do not keep records but know the nursery it came from and have not been to that part of the country for that long. It has formed a very nice clump. Conophytums do not always do this but have to be split up.