Taxonomic Revision Of Quercus Serrata Subsp. Mongolicoides

Quercus serrata subsp. mongolicoides of the Tokai and northern Kanto districts of Honshu, Japan, is similar to Q. mongolica var. mongolica in leaf morphology. Its taxonomic treatment has been long debated, and yet its genetic differentiation from three related taxa, Q. serrata subsp. serrata, Q. mongolica var. crispula, and Q. mongolica var. mongolica has remained unresolved. Genetic differentiation among the four taxa using 11 nuclear microsatellite loci and comparison of leaf morphology was used to revise the taxonomic treatment of Q. serrata subsp. mongolicoides. The genetic data and leaf morphology support the transfer of Q. serrata subsp. mongolicoides from Q. serrata to Q. mongolica. Within the latter, it is treated as a separate intraspecific taxon distinct from Q. mongolica var. crispula in leaf, acorn, and cupule morphology. Additionally, it is geographically well separated from Q. mongolica var. mongolica on the Asian continent and shows significant genetic and leaf differences from the typical variety. Thus, Q. mongolica var. mongolicoides is proposed as a new combination.