Begonia ferox occurs in limestone regions of Southwest China. It is similar in appearance to Begonia melanobullata, except that the cones (bullae) appear gradually as the plant matures, with new leaves coming out a flat green. As mature plants, they look very similar, but ferox has slightly more pointed leaves, with melanobullata being more rounded. Each bullae has a white hair coming out of the tip, which eventually falls off. It requires terrarium culture and can grow to about 16″ in diameter, pictured here, in a 16″ bowl.
The immature foliage can look like this, but does not always lack bullae.
Once the plant attains a certain size, it seems to put out new leaves with bullae.
And a close up of the leaves, where you can see the white hairs coming out of each bullae. Additionally, you can see that each tip is bright red,
Peng, Ching-I & Yang, Hsun-An & Kono, Yoshiko & Chung, Kuo-Fang & Huang, Yu-Song & Wu, Wang-Hui & Liu, Yan. (2013). Novelties in Begonia sect. Coelocentrum: B. longgangensis and B. ferox from limestone areas in Guangxi, China. Botanical Studies. 54. 44. 10.1186/1999-3110-54-44.