What you have there, Anne, is Oxalis purpurea. A native of S. Africa it only grows to 4 ins high, and spreads very slowly.

Bigbumblebee is spot on, I also have this plant, it is a bulb, my dad also had this plant and when he died I combined his and mine and it is very beautiful and so easy to keep.

Yep, that's what it is - I grow mine outside in the summer (see my photos - and I leave it out all the time, as its in a sheltered spot, and it comes up every year)

love all types of Oxalis---its great for splitting and potting up for other people---if you forget it and it dies back it will start up ok when you water it