Alocasia and colocasia are mostly from asia and ausralasia,xanthosoma are only from America (including regional isles ).Alocasia,colocasia and alocasia have edible forms (The only alocasia i know that could be edible is a macrorhyzos).Alocasia and colocasia are so near that some few hybrids had yet be made.The best to made the differentiation is the structures of the leaves.Alocasia have relatively thicker leaves,as colocasia have very soft leaves.xanthosoma are botanicaly more near from dieffenbachia than alocasia as i know.Xanthosoma and the american genus caladium are also very near from each other.But what an amazing plant alocasia is!!!
