According to Wikipedia, Oxalis occur worldwide (except in the polar regions) but have the greatest diversity of species in Brazil, Mexico and South Africa. I'd never realised previously, but many of the flowers that I'm use to seeing in fields in winter and spring are of the oxalis genus in the oxalidaceae family.

Irrespective of what they're named, and how diverse they are, don't you think they're pretty? Fields, meadows and forests, just wouldn't be the same without them.