The genus Trianaeopiper Trealese was described to have axillary inflorescences, a rare character within Piperaceae. Here we present phylogenetic evidence suggesting that Trianaeopiper is not monophyletic and should not be recognized as a distinct genus (new names and combinations are provided). The structure interpreted as an axillary inflorescence is a reduced axillary branch, a by–product of generalized reduction of shoots in these species. Reduction of plant size to a dwarf condition is a phenomenon observed in other angiosperms of the wet tropics. The dwarf habit is correlated with shady environments, suggesting that dwarfism may be an adaptation to the shady understory of wet tropical forests.