Finally a flower - and so small I nearly missed it!
Maybe the insects in Columbia wear magnifying glasses. :-))
Interesting club shape to that one, was it etiolated at one point in its life?
It's always been in full sun so I don't think etoliation has ever been a problem.
Here's a link to my little blog about its life with me so far.
Here is a link that might be useful: Life of my Mammillaria columbiana
This cactus I bought for 50p was IDed as a possible columbiana-must admit yours does look very like an older version of mine!
you can see it to the right in this pic;
Nice plants, Larry. That little one does look very columbiana-like. I only recently got the ID for mine (here on this forum) and I think mine is more likely to be ssp yucatanensis rather than ssp columbiana.
I am told that this week it has now progressed to a ring of flowers, but unfortunately it will probably be all bloomed out by the time I see it.