On the Cryptic Speciation in the Mosses with East Asia–East North America Disjunction: A Case Study of Two Poorly Understood Mosses from the Southern Extremity of the Russian Far East

A survey of the moss flora of the southernmost part of the Russian Primorsky Territory yielded several intriguing taxa, whose identity is assessed herein based on an integrative morpho-molecular approach. <i>Bellibarbula recurva</i> was previously known in inland Asia only from the Sino-Himalayan region and the new locality is distant from the earlier known ones to ca. 3000 km. Despite the morphological uniformity, Russian specimens are remarkably distinct in sequences of all three obtained DNA markers, approaching an American specimen in the <i>rps4</i> sequence. Another probable relic, <i>Symblepharis</i> cf. <i>crispifolia</i>, appeared to be fairly common in the southern part of the Primorsky Territory, where low mountains are covered with hard-leaved forests. Russian specimens of <i>Symblepharis</i> cf. <i>crispifolia</i> var. <i>brevipes</i> show significant divergence from <i>S. crispifolia</i> s.str., which also has complex phylogenetic structure, obscuring further taxonomic implications. The description and illustrations of both taxa based on Russian specimens are provided, and the area, where both species occur, is briefly characterized; it includes numerous thermophilous species, which are rare or do not occur northwards. Our case study uncovers the problem of cryptic speciation within species distributed in temperate climate and is considered to represent relics of Arcto-Tertiary flora.