This is a new species to cultivation as of 2019. The red stems and glaucous maroon leaves create a very striking appearance. I have had it in my collection less than a year, so cannot say for sure how large it gets, but I am guessing it stays under 10?. It is a slower species that I have been growing exclusively on moist sphagnum in terrarium conditions. Like many Begonias from this region, it is not fond of standing water on its leaves.
How the devil do the wild begonias from this region have any leaves left ( in reference to amount of rainfall that hits Borneo during the wet season) at all makes me wonder, as its IN A RAINFOREST or growing on a wet rock surface in a crack. There must be some protectant acting for these plants. One thing that comes to mind is that once moved to cultivation these plants are exposed to bacteria that they are unprepared for, hence the ooh! No water on my leaves please. Or in other terms they are naive to the biome they are cultivated in, hence no resistance.
LOL, I have wondered this myself. It seems to me that often the melting of leaves is more a symptom of poor husbandry or some underlying health issue and more of a ‘symptom’ than the problem in itself. I have left standing water on sensitive Begonias many times, and so long as they are otherwise happy, it’s not a problem. In the past, when I kept them on an improper substrate, melting of leaves was not uncommon. I switched substrates and the melting stopped, even though there was often condensation on the leaves.