I was in Nice Professor's office today when I noticed that she has a very pretty magenta-colored plant on her windowsill. She told me it is a type of shamrock grown from a corn. I'm considering a large scale indoor bulb forcing project this winter (because I need things to look forward to when it's nasty out), so I looked it up this afternoon (in class--bad me) and this is what I found.
A Purple Shamrock (Oxalis triangularis) is also called a Brazilian Butterfly Plant. They are hardy in zone 9 and up, but also do well as houseplants as they tolerate low light (hmm, maybe perfect for my cave of a living room?). The leaves close up when brushed or at night, and they will make pink flowers in the Spring.
Purple Shamrocks are also edible, according to "Plants For A Future," and can be eaten raw or cooked in small quantities. The "small quantities" part sounded a little scary to me, but they qualify it by saying that if you eat too much it can bind calcium and cause a nutrient deficiency--so it won't kill you right away at least! Apparently they have a "pleasant acid flavor".
There are some nice pictures here that really show the color, although they are a bit dusty. And--good news--they are listed on several bulb sites as "suitable for indoor forcing".