Cape shamrock (Oxalis bowiei) is a South African native that blooms in the fall, when not many of my other houseplants are blooming. Here the flower looks huge and a lot like a morning glory, doesn't it? I do think it's just as pretty, but the photo is deceptive...it's only about an inch across. And the petals aren't fused, even though it's hard to tell that either.
This particular plant has been in bloom on my windowsill for about a month so far. It will probably go on like this at least until the holidays cactuses and Hippeastrum start to show off. In Spring, just about when the St. Patrick's Day shamrocks (Oxalis regnelii) conveniently start to bloom, the foliage of cape shamrock will die back and the bulbs will rest until next fall.