[the designation cf. means to compare (you can find the paper describing ruthiae here).  This plant might be ruthiae.  It strongly resembles that species, and was found within 60 miles of the type locality for ruthiae, but a definitive ID has not been made on the basis of significant floristic traits].

From its namesake in Begonia of Borneo, by Ruth Kiew, et al, [describing B. ruthiae]

“surely one of the most beautiful Bornean begonias well worthy of cultivation.  It is a low herb with up to 5 leaves that rest on the soil surface….leaves are a deep magenta underneath.  The surface has an interesting crinkled texture sprinkled with long white or pinkish hairs.  The flowers are raised above the leaves on a red stalk…endemic in the Danum Valley Conservation area in lowland dipterocarp forest where is is locally common in deep shade on banks where there is hardly any leaf litter, or on raised roots or on wet rocks along the river at 200-500 m elevation.  There is one report (SAN 84957) of leaves being found in the gut of a tortoise..”

Interestingly, while searching for more information on Begonia ruthiae, I came across a paper describing it being fed upon by Tabacco Cutworm.  Also interesting, it is found in an area that has the tallest recorded *tropical* tree in the world, the Yellow Seraya, Shorea faguetiana.  It measures at 94.1m tall, not far behind Hyperion the Coast Redwood at 115.8m (overall it is the 7th tallest recorded tree in the world).