nannandry

The existence in a species of male individuals that are considerably smaller than the females. For example, within the moss genus Homaliadelphus there is a species in which the male gametophyte is sufficiently small to grow as an epiphyte upon the leaves of the female gametophyte. The dwarf male filaments of certain members of the Oedogoniales are further examples. Species in which the male plants are of normal size are termed macrandrous.