cpDNA of Acer saccharum and Acer nigrum are Very Similar
The number of species and sub-species that comprise North American sugar maples has remained in dispute since their first characterization over 100 years ago. The taxonomic distinctiveness of Acer nigrum (black maples) and A saccharum (sugar maples) has been particularly controversial. An analysis of the nucleotide sequences from a non-coding region of the chloroplast genome of Ohio black and sugar maples suggests that these trees are genetically very similar and do not require separate taxonomic designations.
Skepner, A. P.,
& Krane, D. E.
(1997). cpDNA of Acer saccharum and Acer nigrum are Very Similar. Ohio Journal of Science, 97 (4), 90-93.