I think I have found it;
Begonia concinna..only found one bad photo on the web but the leaf margin is entire and closed, the leaf petioles look reddish and I think I can see hairs on the leaf to the utter middle right, that angle is were the hairs are clearly visible..
The plant is in the list!
https://www.google.be/search?q...
The source of the photo which was taken in Brazil..
http://www.begonia.rochefort.f...