Recent recognition of a new species of Morus (Morus murrayana D.E. Saar & S.J. Galla)
from eastern North America highlights a general misapplication of the characters that discriminate the
native M. rubra and the morphologically and ecologically variable introduced species M. alba.
Morphological and molecular data presented here show that M. murrayana is best treated as a
synonym of M. rubra, well within its range of morphology and sexual expression. Salient features of
M. alba and M. rubra are presented in order to clarify the distinctions among these species.
KEY WORDS: Moraceae, Morus alba, Morus murrayana, Morus rubra