Cryptogonium (Müll.Hal.) Hampe, Fragm. Phyt. Austr.

Akiyama, Hiroyuki & Tan, Benito C., 2013, The new synonymy of Horikawaea with Cryptogonium and a proposal of Pseudocryptogonium, gen. nov. (Musci, Pterobryaceae), Phytotaxa 98 (1), pp. 16-22 : 18-21

Cryptogonium (Müll.Hal.) Hampe, Fragm. Phyt. Austr. 11: 49 (1881) [ Pterobryaceae ].

Basionym: Phyllogonium Brid. sect. Cryptogonium Müll.Hal., J. Mus. Godeffroy 3(6): 69 (1874).

Pursellia S.H.Lin, J. Hattori Bot. Lab. 55: 299 (1984). “ Type species:— Phyllogonium cylindricum Lindb. ” For more details, see Isoviita (1986).

Horikawaea Nog., J. Sci. Hiroshima Univ. B (2), Bot. 3: 46 (1937), syn. nov.

Familial affinity of Cryptogonium has been variously proposed by different authors, for example, in the Neckeraceae , Phyllogoniaceae , or Pterobryaceae . Judging from morphological features, such as septate, short filamentous gemmae abundantly produced from dormant branch buds in leaf axils, and filamentous pseudoparaphyllia produced on dormant branch buds, as well as the presence of a reduced properistome, smooth exostome teeth, and well-developed alar regions of the stem and branch leaves, its placement in the Pterobryaceae is preferred ( Akiyama 1990 and others). In addition, molecular analyses support this familial treatment [ Goffinet et al. (2009), Cox et al. (2010; fig.1-B), Wang et al. (2010; fig. 1)].

All members of Cryptogonium listed below share the following morphological features: (1) more or less shiny plants with complanate foliation; (2) somewhat cucullate apices of leaves in lateral position on stems and branches; (3) colored, well differentiated alar cells of leaves with quadrate, markedly pitted cells; (4) dormant branch buds of AI-type ( Akiyama 1990) with a number of short, septate gemmae emerging directly from the surface of buds; and (5) filamentous pseudoparaphyllia (often branched and 1–2 cells wide at base).

1. Cryptogonium nitidum (Nog.) H.Akiyama & B.C.Tan , comb. nov. ( Figs. 17–19 )

Basionym : Horikawaea nitida Nog., J. Sci. Hiroshima Univ. B (2) , Bot. 3: 47 (1937). “ Type:— FORMOSA ( TAIWAN). Taipei: Sinten–Urai , Aug. 12, 1932, Noguchi 5850 (holotype HIRO!, isotypes BM, NICH!).”

Other specimens examined:— TAIWAN. Taipei Hsien: San-hsia , 300 m elev., Jan. 28, 1986, T. Y . Ching 12940 ( HIRO!); ibid., Nov. 3, 1987, T. Y . Ching 23892 ( HIRO!) .

Distribution. Endemic to Taiwan.

Note. Horikawaea nitida is the type species of the genus Horikawaea Nog. We follow Lin (1984a) who treated Cryptogonium nitidum (≡ Horikawaea nitida ) and C. dubium (≡ H. dubia ) as two different species and C. nitidum as a Taiwanese endemic. For more details, see notes under C. dubium . Although the sporophyte of H. nitida is still not known, we can assume that it will be similar to that observed in H. dubia because of the strong similarity of their gametophytes and to the extent that the two have been accepted as synonyms by several researchers [ Pócs (1969), Tan & Lin (1995), Ji & Enroth (2006)].

2. Cryptogonium dubium (Tixier) H.Akiyama & B.C.Tan , comb. nov. ( Figs. 1–16 & 26 )

Basionym: Pterobryopsis dubia Tixier, Bot. Közlem. 54: 34 (1967). Ξ Horikawaea dubia (Tixier) S.H.Lin, J. Hattori Bot. Lab. 55: 299 (1984). “Type:— VIETNAM. Ninh-Binh: reservatum Cuc-Phuong, Oct. 22, 1963, T. Pócs 2634/d (holotype PC, isotype EGR!).”

Other specimens examined:—As described above.

Distribution. E. India, North Vietnam, China (Guangdong, Guizhou, Hainan, Sichuan, Yunnan).

Note. Lin (1984a, table 9) compared the morphological features of Cryptogonium dubium and C. nitidum (as Horikawaea nitida ) in detail and treated them as two distinct species. Luo (1989) and Jia (2011) followed the treatment. The main differences between the two species are: (1) more slender and shorter plants with pendent flagelliform branches; (2) small medullary cells of stems with incrassate walls; and (3) strongly complanate foliation in C. dubium . However, Pócs (1969), Tan & Lin (1995), Ji & Enroth (2006) regarded these morphological differences as just phenotypic plasticity caused by environmental factors and treated them as a single variable species. We tentatively treat them as different species here. As shown in the keys below, C. dubium and C. nitidum can be distinguished by their difference in leaf shape at the dorsal and ventral position of stems, especially when wet.

3. Cryptogonium phyllogonioides (Sull.) Isov., J. Hattori Bot. Lab. 60: 452 (1986). ( Figs. 24–32 )

Basionym: Neckera phyllogonioides Sull., Proc. Arts Sci. 3: 181 (1855) Ξ Orthorrhynchium phyllogonioides (Sull.) E. Britton in A. Gepp, Philipp. J. Sci. 68: 232 (1939) Ξ Horikawaea phyllogonioides (Sull.) Nog., Bull. Bot. Soc. Univ. Saugar 13: 29 (1961) Ξ Pursellia phyllogonioides (Sull.) S.H.Lin., J. Hattori Bot. Lab. 55: 299 (1984). “Type:— PHILIPPINES. Luzon: Wilkes U.S. Explor. Exped. s.n. (holotype US!, isotype FH-herb. Fleisch.!).”

Phyllogonium cylindricum Lindb., Öfvers. Kongl. Vet. -Akad. Förh. 21: 603 (1865) Ξ Cryptogonium cylindricum (Lindb.) Paris, Ind. Bryol. : 293 (1894), nom. invalid, based on superfluous combination under Cryptogonium Lindb. (Art. 34.1) Ξ Orthorrhynchium cylindricum (Lindb.) Broth., Natürl. Pflanzenf. I (3): 835 (1906). “Type:—TAHITI: insula O'tahiti, ubi inter alios muscos sparse crescens, Sept. 1852, S. B. Pontén s.n. (lectotype H!, isolectotype H).” For complete list of synonyms, see Lin (1984a).

Other specimens examined:— MALAYSIA. Sabah: Crocker Range National Park, H. Akiyama Crocker-248 (BORN!, HYO!). INDONESIA. West Seram: H. Akiyama C-10016, C-10135, C-10139 and C-10140 (c. sp.) (all HYO!). Central Seram: H. Akiyama C-9261, C-9368, and C-9488 (c. sp.) (all HYO!).

Distribution. Widely distributed in South India, Sri Lanka, SE Asia, Pacific Islands ( New Hebrides, Samoa, Tahiti), and New Zealand (after Lin 1984a).

Note. This species has been fully treated by Noguchi (1961) and Lin (1984a).

Figures

FIGURES 17–32. 17–19; Cryptogonium nitidum (holotype of Horikawaea nitida). 20–23; Pseudocryptogonium tjibodensis (holotype of Horikawaea redfearnii). 24–26; C. phyllogonioides (H.Akiyama C-10140). 27; C. dubium (left; H.Akiyama China-1335) and C. phyllogonioides (H.Akiyama C-10140). 28–29; C. phyllogonioides (holotype of Neckera phyllogonioides). 30–32; C. phyllogonioides (lectotype of Phyllogonium cylindricum).

FIGURES 1–16. Cryptogonium dubium (H.Akiyama China-1335). 1; male plants. 2; close-up of a perigonium (stem leaves are removed). 3; stem with several perigonia arranged in rows. 4; female plants. 5; close-up of a perichaetium, with filamentous pseudoparaphyllia at base. 6; two sporophytes. 7 & 8; close-up of peristome teeth. 9; almost detached operculum. 10; two perichaetial leaves and a sporophyte inside. 11; peristome teeth. 12; close-up of basal part of peristome teeth, with poration. 13; exothecial cells. 14; spores. 15; operculum. 16; cucullate calyptra.