Fissidens adelphinus Besch., Ann. Sci. Nat. Bot., sér. 7, 17: 354. 1983, syn. nov. Type. Japan: U. Faurie 197 (lectotype PC; isolectotypes H-BR, KYO). Fissidens nankingensis Broth. & Par., Rev. Bryol. 37: 1. 1910. Type. China: Nanking (Nanjing), Schenkiang, D. P. Courtois s.n., Feb. 1909 (lectotype H-BR).

Plants medium-sized for the genus. Female leafy stems simple to sparsely branched, reaching 3 cm or more in length, ca. 3 mm wide; axillary hyaline nodules not differentiated; cortical stem cells small, thick-walled; central strand not differentiated. Leaves often more than 50 pairs, more or less densely arranged; mature leaves lanceolate, 1.50–2.25 mm × 0.35–0.50 mm, acute at apex, base of dorsal laminae round, not decurrent; vaginant laminae about one half of leaf length; costa stout, percurrent; margins crenulate throughout; cells of apical laminae round-hexagonal to round-quadrate, 7–10 µm long, mammillose, often with an indistinct papilla at each corner; cells of vaginant laminae similar to those of apical laminae, but slightly larger, less mammillose, with more distinct papilla at each corner. Dioicous. Male plants smaller than female plants, about 10 mm long, 3 mm wide with leaves; antheridia in axils of basal to upper leaves of male plants, bud shaped, about 0.4 mm long; archegonia also in axils of basal to upper leaves of female plants, 0.6–1.0 mm long.

Type. Indonesia: Java, Teysmann s.n. (lectotype designated here, L).

Chinese specimens examined: FUJIAN: Fu-zhou City, M. Zang 792 (HKAS, NICH); Wuyi Shan (Mt.), D.-K. Li & C.-H. Gao 13493 (SHM, SYS). GUANGDONG: Ding-hu Shan (Mt.), M.-P. Li 12 (IBSC, SYS); Guang-zhou City, P.-J. Lin & R.-H. Liao 115 (IBSC, SYS). GUIZHOU: Fan-jing shan (Mt.), C. Gao & J.-Y. Feng 32035 (IFSBH, SYS); Sui-yang Co., C. Gao & J.-Y. Feng 32926 (IFSBH, SYS). HAINAN: Diao-luo Shan (Mt.), Z.-H. Li 2656 (IBSC, SYS); P.-J. Lin & L. Zhang 509, 514, 939, 1022 (IBSC, NICH). HUNAN: Heng Shan (Mt.), T. Cao 21976 (IFSBH, SYS); Meng Shan (Mt.), 1974 Team 1076 (IBSC, SYS). JIANGSU: Chang-shu Co., D.-K. Li 17468 (SHM, SYS). JIANGXI: Jing-gang Shan (Mt.), D.-K. Li 17216 (SHM, SYS); Lu Shan (Mt.), D.-K. Li 16983 (SHM, SYS). SHANGDONG: Kun-yi Shan (Mt.), C. Gao & E.-Z. Bai 34254 (IFSBH, SYS); Lao Shan (Mt.), C. Gao & E.-Z. Bai 34406 (IFSBH, SYS). SICHUAN: Cheng-du City, D.-K. Li 15211 (SHM, SYS); Chong-qing City, Y.-X. Xuing G39A (HKAS, NICH); Liang Shan (Mt.), G.-C. Zhang & T. Cao 21861 (IFSBH, SYS); Omei Shan (Mt.), C. Gao 19458 (IFSBH, SYS); Ya-an Co., C. Gao et al. 17085 (IFSBH, SYS). TAIWAN: Chia-yi Co., Koponen 16933 (H); Nan-tou Co., S.-H. Lin 11191 (NICH, TUNG); Tai-chung Co., Anmashan, T.-Y. Chiang 16252 (NICH); Tai-pei City, Wulai, Paradise, T. -Y. Chiang 29958 (NICH). YUNNAN: Gao-li-gong-shan, M.-Z. Wang 9235a (PE, SYS); Gong-shan Co., M.-Z. Wang 11524b (PE, SYS); Teng-chong Co., X.-J. Li 80-575 (HKAS, NICH). ZHEJIANG: De-qing Co., P.-C. Wu 1184 (MO, PE); Pu-tuo Shan (Mt.), D.-K. Li 6971 (SHM, SYS); Sheng-si Co., D.-K. Li 3826 (SHM, SYS).

Habitat: usually on soil, or on rocks and tree trunks; Distribution: China, Japan, Korea, Indonesia (Java), and Malaysia (Peninsula).

Fissidens teysmannianus can be separated from the closely related species, F. taxifolius, by its leaf cells, especially those of vaginant laminae in which the hyaline, pearl-like papilla at each cell corner can be easily seen. Occasionally, the plants of F. teysmannianus have a few branches. The bases of dorsal laminae are variable in the Chinese specimens, and they are usually rounded, but sometimes are wedge-shaped to broadly wedge-shaped. Although the papillae of upper leaf cells are sometimes worn off (Iwatsuki & Suzuki 1982), they still can be seen on the cells of the vaginant laminae.

Illustrations: Pl. 74, figs. 9–14.