Begonia aff. nurii
This pretty Begonia has bright red petioles and leaf venation. It resembles nurii, but is redder, and I was not good about photographing or examinin the flowers for comparison. The leaves are surprisingly succulent and somewhat prickly to the touch. As it matures the leaves get harrier and rather thick. It is a smaller species, growing to about a foot or so tall at most. I have not seen this species offered in the US before.
Available plants are well rooted in 2″ pots.