Obregonia denegrii
Date: 2002 June 3
This Mexican species is most distinctive. I grew this plant from seed sown either in 1982 or 1989 (not sure which) and it is still in only a 7cm pot. It isn't always the easiest species to cultivate, but can grow quickly when happy.
Here are some pictures
of Obregonia which I saw growing in habitat in Mexico in 1996,
where it clearly received plenty water at some times of year.