This Begonia has deep maroon leaf undersides, which are quite noticeable given how upright the leaves are. It was a hitchhiker from seeds Darrin Norton at Mountain Orchids received out of Vietnam, sp. U636. It seems an easy species to grow so far. I accidentally left my pot of it out for too long, and all the leaves wilted and it looked pretty bad, but after a lot of water it rebounded in less than a week, and quickly produced a flower. It has been suggested to be a red form of B. hatacoa but that ID has not yet been confirmed (info found on mountainorchids.com).