-dimorphism-

n. [ Cf. F. dimorphisme. ] 1. (Biol.) Difference of form between members of the same species, as when a plant has two kinds of flowers, both hermaphrodite (as in the partridge berry), or when there are two forms of one or both sexes of the same species of butterfly. [ 1913 Webster ]

Dimorphism is the condition of the appearance of the same species under two dissimilar forms. Darwin. [ 1913 Webster ]

2. (Crystallog.) Crystallization in two independent forms of the same chemical compound, as of calcium carbonate as calcite and aragonite. [ 1913 Webster ]