Sphagnum henryense

Sphagnum henryense View in CoL (description bases on the East Asian plants, Fig. 5 View Fig )

Plants medium-sized to robust, pale green with brownish-pinkish tint. Capitulum typically flattered sometimes with aggregated branches of the inner part, terminal bud slightly visible. Stem brown to dark brown, hyalodermis well differentiated, superficial cortical layer with distinct spiral reinforcing fibrils, and usually with 4–6 pores per cell. Sclerodermis well delimited, consisting of small thick-walled cells, dark-yellow to brown. Stem leaves lingulate-spatulate with broad rounded apex, 1.7–2.2 (–2.4) mm long and 0.9–1.2 mm wide, border fringed, hyaline cells rhomboid, efibrillose, typically resorbed or have the rests of cell walls with fibrils and pores. Branch fascicles with 2(–3) spreading and 2 pendent branches. Spreading branches quite tapering with spreading to moderately imbricate leaves, which are sometimes squarrose when dry. Branch leaves in the middle part of spreading branches ovate, 1.9–2.8 mm long and 1.4–1.9(–2.2) mm wide, apex cucullate; hyaline cells on the internal surface smooth or have worm-like ornamentation; on convex surface with 10–15(–18) round to elliptic pores 12–15 (–17) µm long and 9–13 µm wide in two rows along commissures; on concave surface with several large round pores across the lateral leaf margins; chlorophyllous cells in branch leaf transverse section isosceles-triangular to ovate triangular, widely open on concave surface and open or slightly enclosed on convex surface.

Differentiation

Sphagnum henryense can be confused with S. palustre s.str., S. centrale and S. papillosum in the field. Microscopically S. henryense clearly differs by its triangular chlorophyllous cells of branch leaves in transverse section, while S. centrale has elliptical cells. Sphagnum papillosum typically has a prominent papillosity on internal walls of hyaline cells of the branch leaves which is absent in S. henryense . Sphagnum palustre s.str. is most

100 µm

F

E similar to S. henryense , however the numerous small pores localized in two rows along commissures in convex side of the branch leaves clearly separate the latter from S. palustre s.str., which typically has a less number of longer elliptic pores adjacent to commissures.

Ecology. In Russia Sphagnum henryense occurs in medium to rich fens with Carex spp. , Equisetum palustre , Comarum palustre , Menyanthes trifoliata , and in floodplain swampy forests.

Distribution in Asia. Sphagnum henryense is known so far in Japan, Honshu and Shikoku Islands, and in Russian Far East, in Kuril Islands, Kunashir.

Specimens examined: Russia, Sakhalin Province, Kunashir Island, Yuzhno-Kurikl’sk District, Otradnyi Village vicinity, Lake Serebrjannoe, 44.05187°N, 145.85597°E, 20.IX.2020, Mamontov 814-1-s10 (MHA9121113); the same region, Kuril State Nature Reserve, Rudnaja Village vicinity, Severjanka River valley, Broadleaved-high herb floodplain forest with willows, on hummock, 44.32080 N, 145.99403 E, 23.IX.2020, Mamontov 814-1-s35 (MHA9121146); Japan, Honshu, Akita Pref., Yuri-gun, Kisakata-machi, Shishigabana, on wet humus in forest, 250 m, 39.15 N, 140.016667 E, 25.VIII.1992, Higuchi (VGBI); Shikoku, North of Asemi, Motoyma-cho, Nagaoka-gun, Kochi Pref. NI-53-28-6 (Motoyama). Forming a carpet at the magrnal slope of Chamaecyparis forest with Quercus glauca , Sasa borealis, Rhododendron decandrum, Plagiogyra euphlebia, Lycopodium clavatum, Hydragea scandens and Deutzia scabra , 33.75 N, 133.75 E, ca 170 m, 15.V.1953, Suzuki (LE as S. palustre ); The same region, Ryujindaira-moor, Mt. Saragamine, Kuma-cho, Kamiukena-gun, Ehime Pref. NI-53-34-2 (Matsuyama-nabu), Forming cusion in the center of a fen characterized by Sasa and Hosta , accompanied by Solidago virgaurea , Scirpus wichurae, Juncus efusus, Eleocharis sp., Allium thunbergii, Ixeris sp. and Lysimachia fortunei , 33.72 N, 133.9 E, ca 1170 m, 2.IV.1952, Suzuki (LE as S. palustre ).