Sonerila are a diverse group of plants in the Melastomaceae family distinguished by having flowers with three petals (as opposed to five for most other plants in this group).  There seems to be alot of variation within a species, and so the ID of aff.cantonensis is a guess.  Sonerilas are an Asian genus that make excellent terrarium plants.  This species is very robust and easily kept provided it does not dry out.  It seems to be nearly always in bloom.

The last photo is representative of the plants available.  They are well rooted and shipped meticulously in their pots.