Calypogeia tosana (Steph.) Steph., Bull. Herb. Boissier ( ser . 2) 8 (9): 678 (410). 1908.

Bakalin, Vadim A., Klimova, Ksenia G. & Nguyen, Van Sinh, 2020, A review of Calypogeia (Marchantiophyta) in the eastern Sino-Himalaya and Meta-Himalaya based mostly on types, PhytoKeys 153, pp. 111-154 : 111

Calypogeia tosana (Steph.) Steph., Bull. Herb. Boissier ( ser. 2) 8 (9): 678 (410). 1908.

= Calypogeia granditexta Steph. Species Hepaticarum 6: 448. 1924. Syn. nov. Type: Japan “Sendai” Uematsu 23 November 1907 (LECTOTYPE (designated here): G G00283130!; another syntype, G00283028!, contains rather typical C. orientalis ).

Basionym.

Kantius tosanus Steph., Hedwigia 34 (2): 54, 1895.

Type.

Japan: Tosa Makino (LECTOTYPE (designated here): G [G00047274/26013, packet b!] The holotype should be in 'herb. Polytechnicum Zurich’, but such specimen is absent in Zurich herbaria (https://www.herbarien.uzh.ch/en/belegsuche.html), therefore we were obliged to lectotypify the species by the specimen from G).

Remarks.

This is a widely amphi-Pacific East Asian species whose area stretches from the southern Kurils and East Manchurian mountains in Russia via the Korean Peninsula and Japanese Archipelago to southeastern China, namely, Taiwan ( Wang et al. 2011), Guangxi ( Zhu and So 2003), Hong Kong ( Zhang and Lin 1997), Anhui, Jiangsu, Guangdong, Hainan ( Piippo 1990), and Guizhou ( Bakalin et al. 2015; Buczkowska et al. 2018) and southward to northern Vietnam ( Shu et al. 2017; Bakalin et al. 2018). This is one of the most common species in amphi-Pacific East Asia; however, it hardly penetrates into the Asian mainland. Admittedly, this species is quite morphologically polymorphous, although its polymorphism has probably been somewhat overestimated. Iwatsuki (2001) provides the key to Calypogeia in Japan, where the ‘races’ (?) with both verruculose cuticle and smooth cuticle are identified as the single C. tosana . We hypothesize that these two ‘races’ may represent two different species. The type of C. tosana is characterized by a smooth leaf cuticle; this feature, although not mentioned in the original description under Kantius tosanus ( Stephani 1895), was provided later when a new combination under Calypogeia was created ( Stephani 1908). The concept of C. tosana is here accepted in the narrow sense closely following the type.

There is a problem with the type of plants in the type specimen due to mixture within. The type specimen (Makino 25, G), as correctly noted by T. Furuki in litt., contains two intermixed species, with one belonging to true C. tosana (coinciding with the original description, packet b) and the other probably belonging to an undescribed taxon. We prefer not to describe this taxon here (it is also beyond the scope of the present account) since the re-collection of fresh material and the study of the ‘intravitam’ character of the taxon (oil body characteristics) and DNA sequences should provide a much better understanding of the taxonomic position of the taxon than the study of poorly preserved sterile and old material in Stephani’s herbarium.

The brief description based on the plants belonging to Calypogeia tosana is as follows: plants translucent, glistening, brownish; leaves very shortly bilobed by U-shaped sinus; underleaves uniformly bisbifid (both small and larger) with undivided portion 1-3 cells high, cells in the midleaf thin-walled with small and concave trigones, 30-50 × 22-45 µm and smooth cuticle.

The plants in Calypogeia granditexta in G00283130 (lectotype) are very similar in their relatively narrow, shortly decurrent, uniformly bisbifid underleaves, shortly bifid leaves and smooth cuticle to C. tosana , and no differences of the species rank were found. Before ( Inoue 1974) C. granditexta was regarded as the synonym of C. angusta , from which, however, differs in incised (versus rounded) leaves and deeply bisbifid (versus bifid, although sometimes with additional lateral teeth in each side) underleaves. Calypogeia granditexta var. anisophylla S. Hatt Journal of Japanese Botany 20: 262. f. 45. isotype (Japan, "Fukushima County, Oze", 1500 m a.s.l. 7 July 1941 S. Hattori, 451 (G00112334!)) contains fairly typical Calypogeia integristipula Steph. and has nothing to do with Calypogeia tosana . The holotype of var. anisophylla was not studied physically, although the photographs provided at TNS herbarium site (http://www.type.kahaku.go.jp/TypeDB/bryophyta/41) correspond well to C. tosana , but not to C. angusta , neither to C. integristipula .