Di`a·del'phi·a noun plural [ New Latin , from Greek di- = di`s- twice + ... brother.] (Botany) A Linnæan class of plants whose stamens are united into two bodies or bundles by their filaments. Found on http://www.encyclo.co.uk/webster/D/56
Diadelphia is the name given by Linnaeus to his seventeenth class of plants, distinguished by having their stamens united in two bundles by their filaments. Found on http://www.probertencyclopaedia.com/browse/BD.HTM