Coryphantha elephantidens, also called "Elephants Foot" from the Mexican state of Michoacan, is a tuberculed globular cactus up to six inches around. It can reach flowering size in 8-10 years. A well defined groove at the top of the tubercule is an indication that the plant is mature enough to flower. It has a large tap root and therefore requires a deeper pot than most cacti, but care should be taken in watering as the deeper the pot the longer it takes to dry out. In late summer or fall C. elephantidens produces large magenta or pink flowers with yellow centers and darker tips followed by green fleshy berries.
     I got this one from B & B Cactus farm in Tucson and unfortunately it was watered from above with our very hard water. It has been suggested that lemon juice on a cotton swab could be used to take off the calcium stains. I tried it but it didn't do much. I love the purple color of the old growth and would love to see it clean and pristine.
     Update August 2006, after a seasons growth the purple color has faded to green and the plant is just gorgeous. I replaced the older pic with a new one and put the old one below so you can see the magnificent color the plant can attain. Maybe it will turn purple again over winter or maybe just needs more sun in the growing season.

How it looked when I bought it	A nice clump at Tucson Botanical Gardens	First flower a sunlit view outside	Next a studio shot inside
A view from the top	A view from the side	Another closeup the next day, flower open more	Closeup of the gnarly spines
One with the new camera	A closer view