In the course of revision of Marchantiales for the Russian Far East, Wiesnerella denudata, the only species of the monotypic family Wiesnerellaceae is recorded for the first time in Russia. The plant has been found in Iturup and Shikotan Islands of South Kurils), and this is the northernmost locality in the world, the nearest previously known locality being in Honshu in Japan and on the southern tip of the Korean Peninsula. The morphological description and figures based on specimens from Russia are provided.
РезюмеВ ходе проведения ревизии порядка Marchantiales для российского Дальнего Востока, в двух образцах собранных на Южных Курилах (острова Итуруп и Шикотан), выявлено новое для России монотипное семейство печеночников Wiesnerellaceae. Для единственного вида семейства, Wiesnerella denudata -это самое северное местонахождение в мире. Ближайшие районы, из которых этот вид известен, находятся на о-ве Хонсю (Япония) и юге Корейского полуострова. Приводится описание вида, иллюстрации, обсуждается распространение. KEYWORDS: Wiesnerella denudata, Wiesnerellaceae, the Russian Far East, distribution, taxonomy, HepaticaeThe family Wiesnerellaceae iincludes the only one species, Wiesnerella denudata (Mitt.) Steph. The genus Wiesnerella was described by Schiffner (1896), based on the collection from Javanese volcano Gedeh (=Gede), where it was collected in inner side of crater. Already in the time of gathering Schiffner has realized that the plant as a very peculiar one. As he wrote, by the general habit of vegetative plants Wiesnerella resembled Lunularia, but without semi-crescentic gemmae cups characteristic to the latter. Within Wiesnerella Schiffner (l.c.) described the only W. javanica Schiffn. Later Stephani (1898) transferred Dumortiera denudata Mitt. described from the East Himalayas (Mitten, 1861) to Wiesnerella and synonymized it with W. javanica with the former as priority.One more species of the genus has been described from Xizang Province of China, Wiesnerella fasciaria (Gao & al., 1981). According to the original description and illustrations (Gao & al., 1981), W. fasciaria differs from W. denudata in (1) having narrower thallus -30 mm length and 2 mm width; (2) having dark green band in the midline of thallus dorsal surface; (3) very elevated pores above epidermis surrounded by 6 concentric rows of 6 cells in each. However our observations and cited literature indicate that the above mentioned features are very variable and W. fasciaria may be regarded as a form of W. denudata from shady and wet place. Probably this results the acceptance of Wiesnerella in the current classification is as a monospecific genus (Bischler, 1998;Frey, 2009), although nobody formally still not synonymized 2 E.A. BOROVICHEV & V.A. BAKALIN W. fasciaria with W. denudata . We were not able to study the type of W. fasciaria and regard it as a synonym of W. denudata provisionally.The main characteristics of Wiesnerella include: (1) simple air pores; (2) ventral scales in 2 rows, each with single appendage; (3) sporophytes...