Bull. Natl. Mus. Nat. Sci., Ser. B, 35(2), pp. 71–89, June 22, 2009 Notes on the Distribution of the Vandenboschia radicans Complex (Hymenophyllaceae) in Japan Atsushi Ebihara Department of Botany, National Museum of Nature and Science, Amakubo 4–1–1, Tsukuba, 305–0005 Japan E-mail: [email protected] Abstract The distribution of eight species and four hybrids included in the Vandenboschia radi- cans complex within Japan is reviewed. Distribution maps for each taxon are provided based on herbarium specimens, which are listed in order of municipality code. Key words:Distribution, Hymenophyllaceae, Japan, Vandenboschia. Introduction were embedded in V. ϫstenosiphon and V. ϫ Vandenboschia subgen. Vandenboschia (Hy- quelpaertensis, respectively because it is diffi- menophyllaceae) distributed in world temperate/ cult to discriminate amphidiploids from sterile subtropical regions encompasses a number of hybrids sharing the same genome combinations morphologically ill-defined species, and they are (but different genome dosage). As shown in the tentatively lumped under a species complex discriminant analysis (Ebihara et al., 2009), some named “Vandenboschia radicans complex”. As of the redefined taxa morphologically overlap for Japanese members of the complex, Ebihara with each other. Therefore, descriptions and keys et al. (2005a) clarified their biological entities by do not always provide sufficient information for DNA/ploidy analyses, and Ebihara et al. (2009) their identification. Digital images of examined reexamined their taxonomic properties. Since the specimens (only those deposited in TNS), to number of samples analyzed in these studies is compensate the difficulty, are accessible via on- still limited, it is necessary to examine as many line database (http://www.vspecimens.net/). All herbarium specimens as possible to cover the the TNS specimens collected in Japan, and speci- whole range of the Japanese archipelago and map mens of other herbaria with localities not over- their localities for grasping the distribution of lapping with those of TNS specimens are cited each newly defined taxon. with their registration numbers and localities (municipalities). Their order generally follows municipality code instituted by the Ministry of Materials and Methods Internal Affairs and Communications, Japan with A total of 3589 sheets of herbarium specimens exception of some islands. tentatively identified as the Vandenboschia radi- cans complex were examined in the herbaria Results and Discussion KAG, KYO, MBK, RYU, TAI, TI and Yamaguchi Museum (hereafter abbreviated as YMG, but un- Vandenboschia kalamocarpa (Hayata) Ebihara registered in the Index Herbariorum). Identifica- [Figs. 1, 13] tion was made with the knowledge on correlation Distributed mostly on the Pacific side, around between morphology and genomic formula ob- 35.5° N latitude line south. Known localities of tained from our previous studies (Ebihara et al., diploids are limited including Kii Peninsula, 2005a; 2009). In the present identification, two Yaku Isl. and the Bonin islands, while triploids amphidiploids, V. hokurikuensis and V. orientalis, show wider distribution. Frond length of diploids 72 Atsushi Ebihara usually under 10 cm, not more than 15 cm. All Vandenboschia subclathrata K. Iwats. the examined individuals of Okinawa Island and [Figs. 4, 16] Taiwan are triploids. Rachis wings tend to be A local endemic species in Yaeyama Islands broad and waved, but this character is not always (Iriomote Isl. and Ishigaki Isl.). Many localities a reliable key for segregating this species from V. are known in Iriomote Isl., while only one collec- ϫstenosiphon. Distributed in continental China tion from the Ishigaki Isl. (Jiangxi Prov.) as well as Taiwan. Vandenboschia hokurikuensis Ebihara [Fig. 5] Vandenboschia nipponica (Nakai) Ebihara A tetraploid species originated from hybridiza- [Figs. 2, 14] tions between V. kalamocarpa and V. nipponica. An element of broad-leaved deciduous forest So far known only from Japan. on the Sea of Japan side, ranging south to the Kyushu mountain range. Diploids are recogniz- Vandenboschia orientalis (C. Chr.) Ching able by three-dimensionally arranged segments [Fig. 6] and broadly triangular involucres. The lowest A tetraploid species originated from hybridiza- pinnae are usually more or less shorter than tions between V. birmanica and V. kalamocarpa. upper ones. Triploids which usually have subdel- The distribution roughly corresponds to the area toid fronds and less three-dimensionally arranged where distributions of the two parental species segments are often difficult to segregate from overlap. In most cases, segregation from V. ϫ V. ϫstenosiphon by morphological characters. quelpaertensis by morphological characters is Ranging north to Shiribeshi Prov., Hokkaido difficult, but Amami-oshima plants exceptionally Pref., and south to Aira-cho, Kagoshima Pref. show characteristic frond shape which is remi- There is some possibility of misidentification of nescent of V. subclathrata with widely spaced triploids as V. ϫstenosiphon. Endemic to Japan, segments. Endemic to Japan. and probably speciated from V. kalamocarpa adapting to heavy-snow environment. Vandenboschia miuraensis Ebihara [Fig. 7] A tetraploid species originated from hybridiza- Vandenboschia birmanica (Bedd.) Ching tions between V. birmanica and V. nipponica. No [Figs. 3, 15] overlapping distribution of the two parents is A subtropical species, distributed only in known so far. warm places on the Pacific side of the Japanese Archipelago. The distribution largely overlaps Vandenboschia oshimensis (H. Christ) Ebi- with that of V. kalamocarpa. The northern and hara [Fig. 8] eastern distribution limit is Shirakawa, Nishiizu- A tetraploid species originated from hybridiza- cho, Shizuoka Pref. There are a number of locali- tions between V. birmanica and V. liukiuensis. ties from southern Kyushu to Okinawa Isl., but Distributed in Amami-oshima Isl. (type collec- none known from Yaeyama Islands. Frond length tion only) and Okinawa Island. usually more than 30 cm, diameter of rhizome approximately 1.5 mm — plants smaller than Vandenboschia ϫstenosiphon (H. Christ) these sizes are probably the hybrid, V. ϫquel- Copel. [Fig. 9] paertensis. There are at least two cytotypes, A sterile hybrid consisting of the genome of V. diploid and triploid, but morphological difference kalamocarpa and V. nipponica. Widely and fre- between them is unclear. Distributed in Taiwan, quently distributed throughout Japan except in China, India, Nepal, Bhutan, Myanmar (type lo- the Ryukyu and Bonin Islands. Also distributed cality), Thailand, Laos and Vietnam. in Cheju-do Isl., South Korea. Distribution of Vandenboschia in Japan 73 Vandenboschia ϫquelpaertensis (Nakai) tion based solely on morphological characters is Ebihara [Fig. 10] often unsuccessful. A sterile hybrid consisting of the genome of V. birmanica and V. kalamocarpa. Distributed most- Acknowledgement ly in coastal areas from 35.5°N latitude line south The author thanks the curators of KAG, KYO, to southern Ryukyus and to Bonin Islands. The MBK, RYU, TAI, TI and Yamaguchi Museum for *1 ϭ two plants with 2n 108 chromosomes ob- their help in examining specimens. served by Mitui (1968; 1973) are probably this hybrid. [*1 Yakushima Isl., Kagoshima Pref. (ϭ TNS-VS-321833) and Chichjima Isl., Bonin Is- References ϭ lands, Tokyo Pref. ( TNS-VS-290706)] Also Ebihara A., Ishikawa, H., Matsumoto, S., Lin, S.-J., Iwat- distributed in Cheju-do Isl., South Korea, but suki, K., Takamiya, M., Watano, M. and Ito, M. 2005a. rare. Nuclear DNA, chloroplast DNA, and ploidy analysis clarified biological complexity of the Vandenboschia Vandenboschia birmanica (Bedd.) Ching ϫ radicans complex (Hymenophyllaceae) in Japan and adjacent areas. American Journal of Botany 92: V. nipponica (Nakai) Ebihara [Fig. 11] 1535–1547. A sterile hybrid consisting of the genome of V. Ebihara, A., Oka, T. and Matsumoto, S. 2005b. The diver- birmanica and V. nipponica. Known only from sity and reticulate evolution of the Va ndenboschia radi- Chiba and Kanagawa prefectures. As already cans complex (Hymenophyllaceae) in Izu, Miura and noted in Ebihara et al. (2005b), Miura Peninsula Boso Peninsulas. Annals of the Tsukuba Botanical Gar- den (24): 17–25. (Kanagawa Pref.) and Boso Peninsula (Chiba Ebihara, A., Matsumoto, S. and Ito, M. 2009. Taxonomy Pref.) are the areas richest in genome combina- of the reticulate Vandenboschia radicans complex tion of hybrids. (Hymenophyllaceae) in Japan. Acta Phytotaxonomica et Geobotanica 60: 27–41. Vandenboschia birmanica (Bedd.) Ching ϫ Mitui. K. 1968. Chromosomes and speciation in ferns. V. kalamocarpa (Hayata) Ebihara V. nipponica Science Report of Tokyo Kyoiku Daigaku B 203: 285–333. (Nakai) Ebihara [Fig. 12] Mitui, K. 1973. A cytological survey on the pteridophytes A sterile hybrid consisting of genomes derived of the Bonin Islands. Journal of Japanese Botany 48: from three parental species. Further localities 247–253. may have been overlooked since species recogni- 74 Atsushi Ebihara Figs. 1–6. Distribution maps of the Vandenboschia radicans complex in Japan. Fig. 1. V. kalamocarpa. Fig. 2. V. nipponica. Fig. 3. V. birmanica. Fig. 4. V. subclathrata. Fig. 5. V. orientalis. Fig. 6. V. hokurikuensis. Large dot: localities of the specimens analyzed by molecular/ploidy analyses; small dot: localities of herbarium specimens. Distribution of Vandenboschia in Japan 75 Figs. 7–12. Distribution maps of the Vandenboschia radicans complex in Japan. Fig. 7. V. miuraensis.