Wiesnerella denudata (Mitt.) Steph., Sp. Hepat.

Wiesnerella denudata (Mitt.) Steph., Sp. Hepat. View in CoL 1: 154. 1899.

– Dumortiera denudata Mitt., J. Proc. Linn. Soc. 5: 125. 1860. – Wiesnerella javanica Schiffn. Oesterreich. Bot. Zeit. 46: 87. 1896. –? Wiesnerella fasciaria C. Gao & K.C. Chang, Acta Bot. View in CoL Yunnan. 3: 390. 1981. syn. nov. prov.

Illustrations: Kashyap, 1929 (p. 45, pl. VI: fig. 1 View Fig -2); Horikawa, 1930 (p. 623, fig. 1 View Fig ; p. 624, fig. 2); Inoue, 1976 (pp. 150-151, pl. 75); Piippo, 1988 (p. 101, fig. 5: e-g; p. 102, fig. 6); Huang & al., 2012 (p. 319, fig. 1 View Fig ; p. 320, fig. 2).

Plants thallose, terrestrial, desiccation intolerant; pale to dark green without secondary pigmentation; prostrate; forming more or less pure and large patches. Thalli thin, large, 20-30 mm long, (4-) 8-12 mm wide; closely or distantly furcate; segments linear-lingulate to oblong; apex retuse, ventral scales appendages slightly overlapping thallus apex; upper surface slightly concave; not reticulate; pores visible with hand-lens, whitish colored; thallus margins plane to undulate, often recurved; lighter colored than median parts. Dorsal epidermis delicate, mostly colorless; cells subisodiametric, (25-)30-40(-55) мm, with thin walls, trigones virtually absent; with scattered obscurely granulate oil-cells; pores simple, slightly elevated above epidermis, one per air-chambers, large, 35-42 мm in diameter; surrounded by 3-4(-6) concentric rows of 6-9 cells in each, cell walls thin. Aerenchyma compact, occupying ca. 1/5-1/4 of the thallus height in the middle; air chambers with few free secondary filaments, each terminated by rounded cell, in one layer; ventral tissue parenchymatous, consisting of thin-walled cells; 4/5–3/4 the thallus thickness in the middle; with few oil-cells; without sclerotic cells or mucilage cavities; hyaline thallus border (in frontal view) usually narrow, composed of 1-3(-4) rows of elongate cells. Midrib thallus 250–600 мm thick in middle part of crosssection; ±relatively well-defined below. Rhizoids smooth and pegged, hyaline to whitish; densely covering ventral surface of midrib of thallus. Ventral scales very delicate; hyaline to reddish; in one longitudinal row on each side; semicircular to lunulate; sometimes with a few slime-papillae on margin; body 600-900 мm long and (420-)500-700 мm wide; with numerous scattered obscure oil-cells, 10-25 мm in diameter; appendage one per scale, orbicular, strongly constricted basally, margins irregularly serrate or irregularly weakly crenulate, (200-)400- 600 мm long and (200-)300-400 мm wide, apex rounded. No asexual reproduction. [Monoicous. Antheridia in subsessile or shortly peduncled cushions surrounded by a few scales situated on leading thallus behind or before the female receptacle. Gynoecia terminal, arising in apical notch of leading thallus; stalk of receptacle hyaline to whitish-green, naked, to 4 mm long, with two rhizoidal furrows. Archegonial scales at base a lanceolate to almost linear. Carpocephalum green, disc convex; 4-7-lobed, each involucre with a single sporophyte; pseudoperianth lacking. Capsule globose, brownish black, dehiscence by 4-6 irregular valves. Outer cells of capsule with walls brown, with annular bands. Spores dark brown, spherical, reticulate, winged, wing broad, 34-38 мm in diameter. Elaters 2-spiral, to 340 мm long ( Kashyap, 1929; Horikawa, 1930; Piippo, 1998; Huang & al., 2012)].

Differentiation: Wiesnerella is a rather easily recognized liverwort even in sterile condition and even in the field. It may be distinguished by the following combination of characters: (1) green to dark green colored dorsal thallus surface; (2) thin thallus with pores visible under hand-lens as whitish points; (3) air chambers with few free secondary filaments, each terminated by round cell; (4) very delicate, hyaline to reddish, broadly lunulate ventral scales with semicircular appendage.

Distribution. This is presumable temperate to subtropical Himalaya-East Asian species. It stretches the area from the eastern Afghanistan, India, Nepal and Bhutan, via discontinuous line in southern China (northernmost in Zhejiang) to Pacific region, from temperate to tropical zone: South Kurils (the present paper) to Korea, Japan, Taiwan, Java and Sumatra ( Kashyap, 1929; Piippo, 1988; Yamada & Choe, 1997; Bapna & Kashroo, 2000; Yamada & Iwatzuki, 2006; Long, 2006; Katagiri & Furuki, 2012; Huang & al., 2012; Piippo & Koponen, 2013).

The localities of Wiesnerella denudata in South Kurils are distant from the nearest records in Honshu (Yamada & Iwatzuki, 2006) and Korean Jeju Island (Choi, pers. comm.); it is likely that the species occur also in Hokkaido.

Ecology: According to literature data, Wiesnerella denudata grows on moist to wet soil rich in humus, as well as on cliffs near streams and especially near the waterfalls, in open to diffusely shaded places, but not in full shade. Within South Kurils and Honshu, where authors observed it in the field, the species grew in various types of communities starting northward from crooked Alnus forests (although not zonal there and occurring rather due to severe wind regime in the islands) to Abies-Picea-Taxus forests, enriched by many East Asian plants such as Toxicodendron , Sasa , etc., and to broad-leaved deciduous forests enriched by some evergreen trees in the middle part of Honshu. In places where we collected, the most common species growing intermingled with W. denudata was Conocephalum salebrosum Szweyk., Buczk. & Odrzyk.

Specimens examined: RUSSIA: Sakhalinskaya Province, Kuriles Islands, Iturup Island, Chyornye Skaly cliffs, about 8 km to the North from Reydovo Settlement along Okhotsk Sea Coast, 45°15'32'’N-148°10'23'’, 15 m alt., in crevices of sheer cliffs shaded by Alnus along sea cost, in mixture with Conocephalum salebrosum , 23.IV.2006, Bakalin ## K66-2a-05, K66-14b-05 (VBGI, duplicate in KPABG); Shikotan Island, Area of Malokurilsk Village, 43°52'17'’N, 146°51'18'’E, 100 m alt., Abies-Picea forest with admixture of Taxus and cover of grass and mosses, bank of stream, in mixture with Conocephalum salebrosum , 23.VIII.2007, Bakalin #P K37-5-07 (VBGI). JAPAN: Honshu, Tottori Pref., Tohaku-gun, Yurihama-cho, Urushibara, Fudo Water Fall, 35°28’55.1"N 133°56’09.3"E, 42 m alt., broadleaved (deciduous and evergreen)-coniferous ( Cryptomeria and Chamaecyparis ) shrubby forest, very wet cliff in spray zone of waterfall, in part shade, 11.III.2013, Bakalin #J-2-19-13 (VBGI); Kokufu-cho, Amedaki, Amedaki Water Fall, 35°28’42.5"N 134°24’04.0"E, 391 m alt., wet cliff in open place in the spray zone of waterfall, 12.III.2013, Bakalin #J-10-7-13 (VBGI); Kyushu, Kumamoto Pref., Yamaye, ca. 32°47’N 130°44’E, 100 m alt., stone wall, IV.1951, Mayebara (Hepaticae Japonicae, Ser. 4., 1951, No. 200, specimen in SAP); Miyazaki Pref., Obi, ca. 31°37’N 131°19’E, 100 m alt., on wet soil, V.1946, Hattori (Hepaticae Japonicae, Ser. 1, 1946, No. 44, specimen in SAP).