Hi there, My plant has broad, deep red leaves (in three parts) at the very end of each thin, smooth, pink stem. The stems don't branch off of each other but rather they push their way out of the soil individually. It produces pale, purple, five-petaled flowers every few weeks on the end of pale green stems. Does anyone know its name? Sorry about the lack of botanical terms, I don't really know anything about plants.
I planted both the red/crimson oxalis and an all green Oxalis in the same pot last fall, it should make for what might be an interesting plant!
http://www.plantoftheweek.org/week021.shtml Oxalis regnellii come in greens, reds, and purples. The trade name is "Shamrock". You are correct, both should look just like your green shamrock plant, albeit with a different color.