No abstract

SAYA TAMURA, TOMOKO FUKUDA, ELENA A. PIMENOVA, EKATERINA A. PETRUNENKO, PAVEL V. KRESTOV, SVETLANA N. BONDARCHUK, OLGA A. CHERNYAGINA, YOSHIHISA SUYAMA, YOSHIHIRO TSUNAMOTO, AYUMU MATSUO, HAYATO TSUBOI, HIDEKI TAKAHASHI, KEN SATO, YOKO NISHIKAWA, TAKASHI SHIMAMURA, HIROKO FUJITA & KOH NAKAMURA An alpine plant Saxifraga yuparensis is endemic to a scree consisting of greenschist of Mt. Yubari in Hokkaido, Japan and it has been proposed as an immediate hybrid derived from two species of the same section Bronchiales based on morphological intermediacy: namely S. nishidae, a diploid species endemic to a nearby cliff composed of greenschist and tetraploid S. rebunshirensis comparatively broadly distributed in Japan and Russian Far East. Saxifraga yuparensis is red-listed and it is crucial for conservation planning to clarify whether this is an immediate hybrid and lacks a unique gene pool. The immediate-hybrid hypothesis was tested by molecular and cytological data. In nuclear ribosomal and chloroplast DNA trees based on maximum parsimony and Bayesian criteria, S. yuparensis and S. rebunshirensis formed a clade with several other congeners while S. nishidae formed another distinct clade. Genome-wide SNP data clearly separated these three species in principal coordinate space, placing S. yuparensis not in-between of S. rebunshirensis and S. nishidae. Chromosome observation indicated that S. yuparensis is tetraploid, not triploid directly derived from diploid-tetraploid crossing. Additionally, observation of herbarium specimens revealed that leaf apex shape of S. yuparensis fell within the variation of S. rebunshirensis. These results indicate that S. yuparensis is not an immediate hybrid of S. rebunshirensis and S. nishidae but a distinct lineage and an extremely narrow endemic species, that deserves for intensive conservation.

In northeast Asia, substantial portion of the floras, including endangered species, are shared among its component countries in the continental, peninsula, and island parts largely through Quaternary migration. To effectively conserve nationally endangered plants in Northeast Asia, transnational conservation studies are vitally needed. Lychnis wilfordii (Caryophyllaceae) has disjunct distribution in Russian Far East (Primorsky Krai), northeast China (Jilin), Korea (Gangwon-do) and Japan (Hokkaido, Aomori, Nagano), surrounding the sea, and this is designated as an endangered species in Japan and Korea. Population genetic and molecular dating analyses were conducted 1) to elucidate geographic genetic structure covering the species range, 2) to test possible scenarios of migration, and 3) to develop logical plans for effective conservation. Population genetic analyses indicated the continent and peninsula parts (north and south Primorsky Krai, Jilin, and Gangwon-do) had higher genetic diversity compared to those in the Japanese Archipelago (Hokkaido and Nagano). Five genetically distinct groups were recognized, namely, Nagano, Gangwon-do, Jilin, north and south Primorsky Krai plus Aomori, and Hokkaido. Genetic distance between Hokkaido and Nagano was larger than between Hokkaido and north Primorsky Krai, and between Nagano and Gangwon-do, crossing national borders and the natural barrier of the sea. Considering these results, L. wilfordii likely migrated from the Asian continent to the Japanese Archipelago using two routes: north route from Russian Far East to Hokkaido and Aomori, and south route from the Korean Peninsula to Nagano. Based on molecular dating, migration from the continent to the islands likely occurred from the middle Pleistocene to the Holocene. For effective conservation of L. wilfordii, Hokkaido and Nagano populations should be distinguished as different evolutionary significant units, although these two regions belong to the same country, because Hokkaido and Nagano populations are at the different ends of the two migratory routes based on the migration scenario.

We discussed the typification of the name Saxifraga yuparensis applicable to an alpine plant described from Hokkaido, northern Japan. The holotype is not found in the cited herbarium and other herbaria related to Nosaka. No isotypes or paratypes were cited in its protologue, and no other uncited specimens are unambiguously deduced to have been used by Nosaka when describing the species and do not comprise the original material (Art. 9.4 of the Botanical Code). Therefore, an illustration (Fig. 11 in Nosaka 1974) published as part of the protologue is the only original material that can be chosen in lectotype designation in conformity with Art. 9.12. The illustration is here designated as the lectotype for the name.