Begonia chlorosticta is a species from Sarawak, Borneo. It was given the designation U038 before being formally identified. For me it has been the most challenging Begonia species to grow, as it frequently goes through melting spells without any apparent change in environment or care. It can grow to over a foot tall, with shrubby type growth. Pictured below is the red form. There is a green form and black form as well.
And here, the same plant a few months later with more mature foliage.
After being repotted into a taller bin,