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

By

Shiotani, Yuki
Fukuda, Tomoko
Marchuk, Elena
Petrunenko, Ekaterina
Krestov, Pavel Vitalʹevich
Bondarchuk, Svetlana
Nishikawa, Yoko
Shimamura, Takashi
Fujimura, Yoshiyasu
Nakamura, Koh

Type

Article

Date of Publication

2020

Original Publication

PhytoKeys

Volume

170

Pages

83--91

Subjects

Betula , chromosome number , Conservation , dwarf birch , Endangered species , Hokkaido , Japan , polyploidy , Russian Far East , wetland

Contributed by

Pensoft Publishers

Language

English

Published by

Sofia, Bulgaria Pensoft Publishers [2010]-

Identifiers

DOI: https://doi.org/10.3897/phytokeys.170.58585

 

Abstract

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.