Merger of Betula tatewakiana (Betulaceae) from northern Japan with northeast Asian B. ovalifolia based on ploidy level

It has been controversial whether Betula tatewakiana, a dwarf birch distributed in Hokkaido of northern Japan, is an endemic species or a synonym of B. ovalifolia broadly distributed in northeast Asia. The endemic hypothesis is based on the idea that B. tatewakiana is diploid while B. ovalifolia is...

Full description

Bibliographic Details
Published in:PhytoKeys
Main Authors: Shiotani, Yuki, Fukuda, Tomoko, Marchuk, Elena A., Petrunenko, Ekaterina A., Krestov, Pavel V., Bondarchuk, Svetlana N., Nishikawa, Yoko, Shimamura, Takashi, Fujimura, Yoshiyasu, Nakamura, Koh
Format: Text
Language:English
Published: Pensoft Publishers 2020
Subjects:
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7773712/
http://www.ncbi.nlm.nih.gov/pubmed/33442325
https://doi.org/10.3897/phytokeys.170.58585
Description
Summary:It has been controversial whether Betula tatewakiana, a dwarf birch distributed in Hokkaido of northern Japan, is an endemic species or a synonym of B. ovalifolia broadly distributed in northeast Asia. The endemic hypothesis is based on the idea that B. tatewakiana is diploid while B. ovalifolia is tetraploid and that they are separated based on the ploidy level; however, no chromosome data have actually been published before. Resolving the taxonomic problem is crucial also in judging the conservation priority of B. tatewakiana in a global perspective. Our chromosome observation revealed that B. tatewakiana is tetraploid as well as B. ovalifolia. We also conducted morphological observations and clarified that B. tatewakiana is morphologically identical to B. ovalifolia in white hairs and dense resinous glands respectively on adaxial and abaxial leaf surfaces, in which they differ from closely related species in the same section Fruticosae. We conclude that the hypothesis that B. tatewakiana is a Hokkaido endemic based on the ploidy level is not supported and that B. tatewakiana should be merged with B. ovalifolia.