Bull. Natl. Mus. Nat. Sci., Ser. B, 39(2), pp. 61–85, May 22, 2013 Distribution of the Thelypteris japonica Complex (Thelypteridaceae) in Japan Atsushi Ebihara1,* and Narumi Nakato2 1 Department of Botany, National Museum of Nature and Science, Amakubo 4–1–1, Tsukuba, Ibaraki 305–0005, Japan 2 Narahashi 1–363, Higashiyamato-shi, Tokyo 207–0031, Japan * E-mail: [email protected] (Received 12 February 2013; accepted 25 March 2013) Abstract The distribution of the four taxa, Thelypteris japonica forma japonica, T. japonica forma formosa, T. musashiensis and T. japonica×T. musashiensis, was reassessed by observation of spore morphology of 1984 herbarium specimens deposited in the National Museum of Nature and Science. As a result of frequent changes of identification especially between T. japonica forma formosa and T. musashiensis, the range of each taxon has been drastically updated. The hybrid was recorded in 32 prefectures in total, including newly added 25 prefectures. Key words : distribution, hybrid, spore, Thelypteris. The Thelypteris japonica complex (Thelypteri- in terms of geographical coverage. The most reli- daceae) is common understory ferns ranging able distinguishing character for the species of throughout Japan except in the Ryukyu Islands. the complex is spore morphology as demon- Japanese members of the complex were recir- strated by Nakato et al. (2004) (Fig. 2), and cumscribed by Nakato et al. (2004) based on therefore sterile specimens and/or specimens cytological and morphological characters, and with only immature spores are difficult to iden- two species, one forma and one interspecific tify. hybrid are presently accepted (Fig. 1). Nakato et al. (2004) examined 77 specimens, and indicated Materials and Methods the approximate geographical and altitudinal dis- tribution of the taxa. Takahashi and Hori (2008) We examined spores of all the specimens of complemented the distribution data of the taxa the complex deposited in TNS. All the specimens with detailed distribution records in Gifu Prefec- were geocoded manually based on place-names ture where no species was recorded by Nakato et in their labels. For specimens with castaneous al. (2004) by observation of spores and gross stipes most of which have been identified as morphology on 157 herbarium specimens. How- T. japonica, spores were preliminary observed ever, a complete picture of the distribution of the with a microscope in 99.5% ethanol. Specimens complex in Japan has not yet been provided by producing only irregular spores were identified previous studies. as the hybrid (T. japonica×T. musashiensis) and In this study, we reidentfied voucher speci- those producing normal-shaped spores with mens deposited in the herbarium of National membraneous ornamentation were identified as Museum of Nature and Science (TNS) for the T. japonica forma japonica. Permanent mounts distribution maps created by Kurata and Nakaike of spores were prepared with Bioleit (Oken-shoji (1983) which are probably the largest collections Co.) and deposited in TNS only for the hybrid. 62 Atsushi Ebihara and Narumi Nakato Fig. 1. Specimens of the Thelypteris japonica complex in Japan. A. Thelypteris japonica forma japonica (TNS- VS-432942, Aichi Pref., Seto-shi, M. Muramatsu 80366); B. T. japonica forma formosa (TNS-VS-1157138, Yamagata Pref., Kaminoyama-shi, N. Sagawa s.n.); C. T. musashiensis (TNS-VS-1152616, Shizuoka Pref., Fujinomiya-shi, T. Sato 4091); D. T. japonica×T. musashiensis, the castaneous stipe form (TNS-VS-831722, Kyoto Pref., Kitakuwada-gun, Miyama-cho, S. Masuda s.n.). Distribution of the Thelypteris japonica Complex (Thelypteridaceae) 63 Fig. 2. Spores of the Thelypteris japonica complex in Japan (scale bars＝50 μm). A. spores with membraneous ornamentation produced by T. japonica forma japonica (TNS-VS-397231, Yamaguchi Pref., Iwakuni-shi, A. Minami 16677); B. spores with membraneous ornamentation produced by T. japonica forma formosa (TNS- VS-438920, Fukushima Pref., Onuma-gun, Showa-mura, Z. Kaneda s.n.); C. spores with echinate ornamenta- tion produced by T. musashiensis (TNS-VS-1159828, Oita Pref., Naoiri-gun, Kuju-machi, M. Arakane s.n.); D. irregular-shaped spores of T. japonica×T. musashiensis (TNS-VS-438936, Fukushima Pref., Kitakata-shi, Z. Kaneda 6517). Results and Discussion For specimens with stramineous stipes (stramine- ous at least in the upper half of the stipes) which Among ca. 2500 specimens examined, mature have been identified as T. japonica var. spores were observed in 1984 specimens. As a musashiensis (T. musashiensis), var. glabrata, f. result, 1193 specimens (60.1%) were identified viridescens and forma formosa, those producing as T. japonica forma japonica, 275 (13.9%) as T. only irregular spores were identified as the japonica forma formosa, 344 (17.3%) as T. hybrid and those producing normal-shaped musashiensis and 172 (8.7%) as the T. japonica× spores were separated into two taxa depending T. musashiensis (Appendix 1). It is notable that on the morphology of the spore ornamentation the hybrid consists of individuals with castane- (membraneous for T. japonica forma formosa ous stipes (120, 69.8% of the hybrid) and those and echinate for T. musashiensis). Specimens, with stramineous stipes (52, 30.2%). even with abundant irregular spores, were not Thelypteris japonica forma japonica is the identified as the hybrid when a few regular most widespread and most common taxon in the spores were mixed with the irregular ones. All complex, ranging throughout Japan except in the spores collected from specimens with stra- Hokkaido and Okinawa Prefectures (Fig. 3A). mineous stipes were mounted with Bioleit and Thelypteris japonica forma formosa is also wide- the permanent mounts were deposited in TNS. spread, extending to the southern part of Hok- 64 Atsushi Ebihara and Narumi Nakato Fig. 3. Distribution maps of the Thelypteris japonica complex in Japan based on the specimens examined by the present study. A. Thelypteris japonica forma japonica; B. T. japonica forma formosa. Distribution of the Thelypteris japonica Complex (Thelypteridaceae) 65 Fig. 4. Distribution maps of the Thelypteris japonica complex in Japan based on the specimens examined by the present study. A. T. musashiensis; B. T. japonica×T. musashiensis. 66 Atsushi Ebihara and Narumi Nakato kaido, but less common than the type forma (Fig. Tokyo (in Japanese). Nakato, N., Sahashi, N. and Kato, M. 2004. Cytotaxon- 3B). Thelypteris musashiensis prefers rocky hab- omy of the Thelypteris japonica complex (Thelypteri- itats at rather high altitudes (Nakato et al., 2004), daceae). Acta Phytotaxonomica et Geobotanica. 55: and tends to be distributed in inland areas from 89–105. southern Hokkaido to Kyushu; it has not yet been Takahashi, H. and Hori, S. 2008. Distribution of the found in 8 prefectures, i.e. Chiba, Kanagawa, Thelypteris japonica complex (Thelypteridaceae) in Shimane, Yamaguchi, Kagawa, Nagasaki, Kuma- Gifu Prefecture, Japan. Bulletin of the Gifu Botanical Society 24: 89–94 (in Japanese). moto and Okinawa (Fig. 4A). The hybrid (T. japonica×T. musashiensis) has been found in most of the prefectures where distributions of T. Appendix 1. Specimens identified based on spore morphology. Municipal-level locality information is japonoica s.l. and T. musashiensis overlap, but provided for Thelypteris japonica forma japonica, and not yet been found in Hokkaido, Mie, Osaka, locality details are provided for the remaining taxa. Nara, Wakayama, Tokushima, Fukuoka, Saga, Thelypteris japonica (Baker) Ching forma japonica [Harig- Kumamoto, Miyazaki and Kagoshima Prefec- ane-warabi] tures (Fig. 4B). It is also notable that the hybrid Honshu - Aomori Pref.: Higashitsugaru-gun, Kanita-machi, 1977-8- occurs in Chiba, Kanagawa and Shimane Prefec- 22, N. Saitoh s.n. (TNS-VS-344145); Iwate Pref.: Shiwa-gun, tures where one of the parents, T. musashiensis Tonan-mura, 1980-9-15, Y. Nakajima s.n. (TNS-VS-440259); has not yet been recorded. Takahashi and Hori Miyagi Pref.: Sendai-shi, 1912-9-28, E. Iishiba s.n. (TNS- (2008) already pointed out that hybrids were VS-254666), 1980-9-23, M. Takeichi s.n. (TNS-VS-575758); Ishi- nomaki-shi, 1972-10-15, Y. Ueno 8550 (TNS-VS-575754); often recorded in the localities lacking one or Shiogama-shi, 1977-8-22, M. Takeichi s.n. (TNS-VS-575762); both of their parents, and our present results fre- Shibata-gun, Shibata-machi, 1980-10-11, K. Shoji s.n. (TNS- quently showed a similar phenomenon when VS-575751); Igu-gun, Marumori-machi, 1980-8-10, K. Okazaki localities smaller than prefectures were taken s.n. (TNS-VS-576835), 1980-7-22, K. Okazaki s.n. (TNS- into account. Although insufficient sampling is VS-576834), 1981-8-23, K. Matsunaga s.n. (TNS-VS-1156160); probably a cause of this phenomenon, some of Miyagi-gun, Matsushima-machi, 1976-8-19, W. Takahashi s.n. (TNS-VS-576832); Rifu-cho, 1980-10-26, M. Takeichi s.n. (TNS- the localities of the hybrid are apparently not pre- VS-575756); Shida-gun, Matsuyama-machi, 1977-?-?, M. Takeichi ferred by T. musashiensis (e.g. TNS-VS-517192, s.n. (TNS-VS-575761); Tamatsukuri-gun, Iwadeyama-machi, Tokyo, Ikegami — located in the city center of 1972-10-1, W. Takahashi s.n. (TNS-VS-576833); Mono-gun, Tokyo, almost at sea level). Variation in stipe Yamoto-cho, 1977-10-15, M. Takeichi s.n. (TNS-VS-575763); color of the hybrid is presumably due to the stipe Oshika-gun, Onagawa-cho, 1981-9-23, M. Takeichi s.n. (TNS- color of one of the parents (i.e. T. japonica forma VS-575767); Inai-cho, 1967-10-22, M. Kikuchi s.n. (TNS- VS-177138); Oshika-cho, 1979-11-4, K. Matsunaga s.n. (TNS- japonica vs. forma formosa). The hybrid with VS-1156161); Motoyoshi-gun, Shizugawa-cho, 1980-9-19, M. stramineous stipes has been collected in the Takeichi s.n. (TNS-VS-575760); Motoyoshi-cho, 1980-7-26, Z. northeastern half of Honshu so far, which seems Kaneda s.n. (TNS-VS-575759); Akita Pref.: Akita-shi, 1978-9-5, to be influenced by the distribution of T.