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We developed 10 microsatellite markers for Plagiogyria koidzumii, a critically endangered fern species found on Iriomotejima Island in the Ryukyu Archipelago, Japan and in Taiwan. These markers showed polymorphism among 65 wild individuals from Iriomotejima Island; the number of alleles per locus was 2-14, and mean observed and expected heterozygosity in the largest population were 0.276 and 0.277, respectively. A genetic structure analysis using these markers indicated clear genetic differentiation even within the narrow geographic range (ca. 10 × 8 km) on Iriomotejima Island. These microsatellite markers should be valuable for measuring genetic diversity and comparing genetic structure within and between populations.

Fourteen flavonols, four flavones and six isoflavones were isolated from the aerial parts of two Japanese Glycine species, G. tabacina and G. koidzumii, and the leaves of Taiwanese G. max subsp. formosana. Of their flavonoids, twelve flavonols were identified as kaempferol 3-O-sophoroside (1), 3-O-rutinoside (2), 3-O-robinobioside (3) and 3-O-rhamnosyl-(1→4)-[rhamnosyl-(1→6)-galactoside] (4), quercetin 3-O-gentiobioside (5), 3-O-glucoside (6), 3-O-galactoside (7), 3-O-rutinoside (8), 3-O-robinobioside (9) and 3-O-rhamnosyl-(1→4)-[rhamnosyl-(1→6)-galactoside] (10), and isorhamnetin 3-O-rutinoside (11) and 3-O-robinobioside (12). Other two flavonols were characterized as isorhamnetin 3-O-rhamnosylrhamnosylglucoside (13) and 3-O-rhamnosylrhamnosylgalactoside (14). Four flavones and six isoflavones were estimated as schaftoside (15), apigenin 6,8-di-C-arabinoside (16), luteolin 7-O-glucoside (17) and chrysoeriol 7-O-glucoside (18), and daidzein 7-O-glucoside (19), 4'-O-glucoside (20) and 7-O-xylosylglucoside (21), genistein 7-O-glucoside (22) and 4'-O-glucoside (23), and 3'-O-methylorobol 7-O-glucoside (24). Although flavonoid composition of G. tabacina and G. koidzumii was similar to each other, that of G. max subsp. formosana was different with those of two Japanese Glycine species described above. Flavonoids of their Glycine species were reported for the first time except for those of G. tabacina., 論文

Seed germination characteristics of a facultative rheophyte Scutellaria rubropunctata, a perennial skullcap endemic to the subtropical Ryukyu Islands of Japan, were investigated at temperatures of 15 °C, 20 °C, 25 °C, and 30 °C. The rheophytic type of S. rubropunctata showed relatively simultaneous germination times and reached high germination rates under all temperatures tested. This characteristic may allow it to establish quickly without being influenced by temperature, giving a survival advantage in rheophytic habitats by avoiding seeds being washed away by the rising water. In contrast, the final germination rate of the terrestrial type of S. rubropunctata, as well as that of the congener S. indica var. parvifolia, was highest at 15 °C and declined drastically at 30 °C. Seeds of both of these plants that remained ungerminated at higher temperatures germinated soon after the temperature was changed to 15 °C, indicating that the germination suppression was a state of enforced dormancy that was released after transfer to the optimal temperature. These characteristics suggest an asynchronous germination which is thought to reduce the risk of disturbance in fluctuating environments. Our study may be the first to demonstrate the differentiation of seed germination characteristics in relation to adaptations to a rheophytic habitat. Because rheophytes occupy such a harsh environment under strong selective pressure, the adaptive differentiation of seed germination characteristics may occur in many other rheophytes.

The population genetic patterns of a species at its range limits have important implications for species conservation. Geographically marginal populations are expected to have lower genetic diversity and higher genetic differentiation than geographically central populations. Nypa fruticans is a mangrove palm which is widely distributed from tropical to subtropical zone of Southeast Asia and Oceania. For N. fruticans, Iriomote Island in Japan represents the most northern limit of the distribution of the species. We examined the genetic variation based on 11 microsatellite markers from all 137 known ramets of N. fruticans on Iriomote Island in comparison with the more central population. Adult ramets on Iriomote Island were composed entirely of one multilocus genotype in each population and had no genetic diversity within the populations. The formation of each population by vegetative propagation from only one immigrant individual was considered to be the method of reproduction. In addition, the new juvenile which were found on the opposite side of the island possessed different alleles from other ramets in the island. This indicates that the transfer of a new genotype from another location abroad can take place. The analyses provided useful information for the continued monitoring of the demography and genetic status of these populations.

We found Gastrodia fontinalis T. P. Lin in a bamboo forest from Takeshima Island, which is the northernmost island of the Ryukyu Islands in Japan. This species is apparently rare and was previously considered to be an endemic Taiwanese species. Because there are a few minor differences between the original description and our specimens collected in Takeshima Island, here we report Gastrodia fontinalis from Takeshima Island as the first record outside of Taiwan, with a description of the specimens from Takeshima Island.

In continental island biogeography, geologically age-old straits have been considered to be the most likely barriers in determining geographical patterns of speciation/genetic differentiation among islands. Straits with similar ages may have had different influences if geographical width across the straits had fluctuated differently in the past. However, this issue has seldom been discussed. We explored it by studying the Viola iwagawae-tashiroi species complex in the Ryukyu Archipelago, Japan. The archipelago is divided into three island groups, the northern, central, and southern Ryukyus, by two old straits called the Tokara and Kerama gaps, which are roughly of the same age. Bayesian and maximum parsimony phylogenetic analyses of section Plagiostigma and Bayesian molecular dating using multiple calibration points were conducted based on nuclear ribosomal DNA internal transcribed spacer (ITS) sequences. To reveal the detailed genealogy of the species complex, statistical parsimony networks were estimated separately for the ITS and chloroplast DNA (cpDNA) sequences and a calibrated multispecies coalescent tree based on both ITS and cpDNA sequences was constructed. Results suggest that the V. iwagawae-tashiroi species complex originated in the Ryukyu Archipelago when this region formed part of the East Asian continental margin or was formed by a few larger islands and that the complex was already distributed across the archipelago by the late Pliocene–early Pleistocene. Divergence time estimations suggest that the Kerama Gap has been a long-term effective barrier to dispersal preventing gene flow across it, whereas recent dispersal over the Tokara Gap was inferred. These contrasting results are likely explained by the fact that the minimum geographical width across the straits is geohistorically and currently greater over the Kerama Gap than at the Tokara Gap.

Equatorward contraction and re-expansion during and after the last glacial maximum has been reported for temperate plants, but little is known about latitudinal shifts of tropical plants in insular Asia. We used molecular methods to test the post-glacial migration hypothesis for Begonia fenicis at the northern limit of tropical insular Asia, namely, the northern Philippines, southern Taiwan and the southern Ryukyus of Japan. Based on internal transcribed spacer sequences, analyses of phylogeographical structure suggested long-term survival of island populations and negated recent northward migration; demographic analyses indicated spatial expansion in the early Pleistocene and subsequent stable demography. Based on nuclear microsatellites, Bayesian clustering and other spatial analyses indicated inter-island differentiation, and coalescent analysis of migration indicated the lack of inter-island migration during and after the last glacial maximum. Our results refuted the postglacial migration hypothesis for B. fenicis and suggest in situ survival through the last glacial maximum. The stable historical distribution and demography are probably attributable to the Kuroshio Current bringing warm and humid air, which washed these islands even during the glacial periods. Additionally, because these are low islands, absence of competition with montane plants descending to the lowlands during cooler periods may have mitigated the influence of temperature lowering and facilitated their survival. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174, 305–325.

Croton Codiaeum variegatum (L.) Blume is a popular ornamental foliage plant that displays an anomalous range of variations in its leaf size, shape and color pattern. By fixing such leaf variations, more than 300 cultivars have been produced in the world. Until now, however, only a limited number of studies have been made to describe the leaf phenotypic diversity. Here we investigated the diversity of leaf phenotype in croton cultivars with a numerical taxonomic approach. One-way analysis of variance confirmed significant phenotypic variations in the croton cultivars for 12 quantitative leaf parameters. Among the numerical parameter tested, the leaf index that is the ratio of leaf length to leaf width showed the highest variability. High coefficient of variation values were observed in petiole length, leaf area and leaf down quarter width. In contrast with leaf morphology, the composition of leaf pigments that contribute to leaf coloration did not show diversity. Based on the analyses of the leaf parameters, we clustered the croton cultivars into four major groups. The results of this study provide a numerical basis for classification of croton cultivars. A possible involvement of transposon is discussed in terms of somatic mutation that results in the leaf phenotypic diversity.

An antitropical distribution represents an intriguing disjunction, in which a given species or sister lineages occupy regions north and south of the tropics but are absent from the intervening areas. Solenogyne mikadoi endemic to the Ryukyu Archipelago is regarded as an Australian element. Testing the phylogenetic relationship with Australian congeners and discussing the onset timing and causes of the disjunction would potentially enhance the understanding of antitropical distribution. A nuclear ribosomal DNA phylogeny was reconstructed using Bayesian and most parsimonious criteria with allied genera. Solenogyne was monophyletic and clustered with Lagenophora huegelii endemic to Australia, indicating the antitropical distribution and Australian origin of Solenogyne. Multispecies coalescent analysis based on nuclear ribosomal DNA and chloroplast DNA indicated the divergence of S. mikadoi and Australian congeners in the Plio-Pleistocene. Phylogenetic network analyses suggested that the ancestral lineage of S. mikadoi first colonized the southernmost island in the archipelago and then dispersed northward. The migration to the archipelago likely followed the flourishing of Solenogyne in open vegetation communities that radiated in south-eastern Australia during the late Pliocene. This disjunction might arise through long-distance dispersal across the tropics or, alternatively, through extinction in the tropics as a result of unsuitably high temperatures during climate oscillation and/or competitions from diverse tropical flora surviving since the early Tertiary.

Molecular phylogenetic analyses using ITS sequences were used to reconsider the taxonomic validity of Bredia okinawensis, B. yaeyamensis, and B. sinensis as an independent genus Tashiroea. The result showed that the three species formed a different phylogenetic lineage from other species of Bredia including its type species. We suggest that B. okinawensis, B. yaeyamensis, and B. sinensis should be treated as T. okinawensis, T. yaeyamensis, and T. sinensis, respectively, following Ito and Matsumura (1899) and Diels (1924).

Comparison of leaf morphometric variation and phylogenetic analyses based on nrITS and partial trnC-D cpDNA sequences were conducted for samples of Lysionotus pauciflorus sensu lato collected from China, Japan and Taiwan. In the morphometric comparison, leaves of plants from Japan proper and those from Taiwan proper were not significantly distinguishable by their leaf length to width ratio. In phylogenetic analyses, monophyly of L. pauciflorus s. l. samples was strongly supported, and Japanese and Taiwanese samples fell into a clade separate from Chinese samples. In the Japan–Taiwan clade, plants from Japan proper formed a sister clade to those from Okinawa Island (Japan) and Taiwan. The present results suggest that (1) the L. pauciflorus s. l. samples from China, Japan and Taiwan must be treated as a single species; (2) L. pauciflorus s. l. originated in China; (3) a single dispersal event, dispersal via a land-bridge during low sea levels in a Pleistocene glacial maximum, from China to Taiwan and Japan is proposed; (4) three oversea dispersal events, probably through anemochory, to Japan proper, across the Tokara Gap, to Okinawa islands crossing the Kerama Gap, and from Taiwan to Lanyu Island are proposed. The study gives further insight into the biogeographical dynamics between the Ryukyus and surrounding areas.

Two cytotypes of Lysimachia mauritiana collected from Japanese mainland (JM-type) and the Sakishima group (SR-type), located in the southernmost of the Ryukyu Archipelago of Japan, were cytoge- netically analyzed. JM- and SR-types showed karyotype formulae of 2n=20(4m)=4m+2sm+4st+10t and 2n=18(6m)=6m+2sm+10t, respectively. In FISH analysis, a signal of 5S rDNA was observed at the interstitial region of long arm on a pair of t-chromosome in both cytotypes. On the other hand, different sizes of 45S rDNA signals were observed on the distal and proximal regions of m-, sm-, st- and t-chromosomes in JM-type, and of m- and t-chromosomes in SR-type. Also in SR-type, a tiny 45S rDNA signal was shown at the interstitial region of long arm on sm-chromosome. Telomere signals in two cytotypes appeared at both ends of all chromosomes, and at internal sites of certain chromosomes. The big telomere sequence signal at the proximal region coincided with the small 45S rDNA signal in JM-type. These results gave us a fusion/fi ssion hypothesis with two st- or one m-chromosome(s) for new intraspecifi c karyotype formation of JM-type or SR-type.

Aneuploidy and karyotypic polymorphism in 98 individuals of Lysimachia mauritiana collected in middle and southern parts of the Ryukyu Archipelago, Okinawa Pref., were cytologically analyzed. Aneuploids of 2n=16, 17, 18, 19 and 20, and 13 cytotypes were recognized in the areas. By using longer metacentric chromosomes as markers, the number of all cytotypes in the Ryukyu Archipelago, Japan was 18, together with data reported earlier.

Aim Floristic differentiation in the Ryukyu Archipelago has been explained primarily by geohistory, specifically landbridge formation and vicariance at the Tokara and Kerama Gaps, two deep-sea channels through the island arc. This ignores current environmental effects, which may also be important. We therefore tested whether the floristic differentiation pattern is explained primarily by the historical effect of the gaps as barriers, or whether a better understanding of floristic differentiation is achieved when both historical and current environmental factors are incorporated. Location Ryukyu Archipelago, Japan: an assemblage of continental islands. Methods We compiled a presence–absence matrix of 1815 plant species on 26 islands. Floristic dissimilarity distances between islands were calculated using Simpson’s similarity index and analysed using cluster analysis. We also conducted multiple regression on distance matrices (MRM) to examine the significance of the historical factors of the gaps and current environmental factors: geographical distance among islands and differences in island area and maximum elevation. Results We detected clear patterns of floristic differentiation across the gaps. Using the two gaps as explanatory variables, the MRM showed that both had significant effects on floristic dissimilarity distance. However, when geographical distance was added to the explanatory model, the Kerama Gap effect disappeared. When all five explanatory variables were used, the Tokara Gap and geographical distance had positive effects, but area difference had a negative effect. The Kerama Gap and difference in maximum elevation had no effect. Main conclusions The geographical pattern of floristic differentiation appears to indicate the influence of both gaps. However, the MRM indicates that the floristic differentiation across the Kerama Gap is no more than could be explained solely by geographical distance. Across the Tokara Gap, however, floristic differentiation is larger than geographical distance alone can explain. This additional differentiation is attributable to the effect of the historical barrier. To verify the significance of historical effects of vicariance on island biota, the confounding effects of geographical distance must be considered. The distance decay of floristic similarity and negative effect of area difference on floristic differentiation demonstrate that floristic differentiation is better understood by incorporating both historical and current environmental factors.

The floristic composition, woody species diversity, and spatial distribution of trees in a subtropical evergreen broadleaf forest on Ishigaki Island, Japan, were investigated based on architectural stratification. Five architectural layers made up the forest stand. The floristic composition was almost similar between the third and the bottom layers, whereas it was almost exclusive between the top and the lower four layers. The fourth layer contained the highest potential number of species (90). Castanopsis sieboldii, Daphniphyllum teijmannii, Neolitsea aciculata, and Distylium racemosum were typical facultative shade species that appeared in all layers. Ardisia quinquegona was the most dominant species, as it had the highest importance value at the stand level; it was also considered a small climax species because of its disappearance in the top layer but higher importance value in the lower four layers. The values of Shannon’s index H’ and Pielou’s index J’ were 4.36 bit and 0.69, respectively, for the entire stand; these values tended to increase from the bottom layer upward, except for the H' -value of the top layer. Furthermore, woody species diversity was higher in the upper strata than the lower strata. The spatial distribution of trees was random in each layer, except in the bottom layer where trees were aggregately distributed. The degree of overlap in tree habitats differed among layers, and the results suggested that trees in the second layer could capture moderate light, while light could not easily penetrate the lower three layers. Therefore, most species in the lower layers must be shade-tolerant. The mean tree weight of each layer decreased from the top layer to the bottom layer, whereas the corresponding tree density increased. We concluded that this trend might be a general phenomenon in subtropical evergreen broadleaf forests of the Ryukyu Archipelago, and we designated this trend as the quasi mean tree weight-density trajectory of forest stratification. The relationship of mean tree height to tree density for the upper two layers supported Yamakura’s quasi -3/2 power law system.

1. Subject and sourceThegenusCassytha(Lauraceae)isaparasiticherb,whichcontainsca.20speciesandisdistributedinPacificRimcountries,mainly Australia, Africa, America and Japan (Mabberley, 1997). The leaves are degenerated and almost assimilate into thestem, which has small elliptical haustoria (Weber, 1981). Three Cassytha taxa, Cassytha filiformis L. var. filiformis, C. filiformisvar. duripraticola Hatus. and Cassytha pergracilis Hatus., are distributed in Japan, and the latter two are listed as endangeredplants by the Ministry of Environment, Japan. However, their taxonomic treatment underwent various changes (Hatusima,1971, 1975, 1978; Hatusima and Amano, 1994). Based on the specimens in Australia, Hatusima and Amano (1994) andHatusima (1978) treated C. filiformis var. duripraticola as Cassytha pubescens R. Br., and C. pergracilis as Cassytha glabella R.Br. However, it was difficult to classify them with only morphological characters. In this study, we describe the flavonoidsfrom the aerial parts of six Cassytha taxa and chemotaxonomically discuss them. The Cassytha species examined in this studywere collected in the sites described in Table 1. Voucher specimens were deposited in the Herbarium of National Museum ofNature and Science, Japan (TNS).2. Previous workPhylogeneticanalysesof thefamilyLauraceaeincludingCassytha,CassythaciliolataNees,C.filiformisandC.pubescenshavebeen carried out (Rohwer, 2000; Chanderbali et al., 2001). As chemical components in Cassytha species, many aporphine

Woody species diversity and the spatial distribution of trees in a subtropical evergreen broadleaf forest on a silicate substrate, Okinawa Island, were investigated to determine the forest's architectural stratification. The forest stand consisted of four architectural layers. The values of Shannon's index H′ and Pielou's index J′ tended to increase from the top layer downward, except for the bottom layer. The lower layers contained many species relative to their smaller height ranges. High woody species diversity of the forest depended on small trees. This trend of species diversity was different from that of forest on a limestone substrate on Okinawa Island, where high woody species diversity depended on large trees. Conservation of small trees in the lower layers, especially the bottom layer, is indispensable to maintain diversity in Okinawan evergreen broadleaf forests. Castanopsis sieboldii (Mak.) Hatusima had the highest importance value in all layers, indicating that it is typically a facu...

Karyotype change of Lysimachia mauritiana was cytologically analyzed in 76 individuals collected in the northern and middle parts of the Ryukyu Archipelago in Kagoshima Prefecture, Japan. Sixteen cytotypes were recognized in the areas. At least, four long median- and six terminal-centromeric chromosomes were included in the chromosome complements of the individuals observed. Remarkable choromosomal polymorphism or karyotype variation was shown in the Ryukyu Archipelago, especially the Amami group.

We conducted the first chromosomal studies of Lonicera japonica var. miyagusukiana, an endemic of the Ryukyu Archipelago, Japan. Lonicera japonica var. japonica (Japanese honeysuckle) from Japan was also ana- lyzed for comparison. All individuals of L. japonica var. miyagusukiana collected from three islands of the central and southern Ryukyus were tetraploid with chromosome number of 2n = 36 (2n = 36 = 4m + 28sm (2SAT) + 4st), whereas L. japonica var. japonica was diploid with 2n = 18 (2n = 18 = 2m + 14sm (2SAT) + 2st), indicating karyotype similarity. However, the karyotypes of L. japonica var. miyagusukiana and L. japonica var. japonica dif- fered from those of previously reported diploid and tetraploid L. japonica from China. These results, together with the remote distribution, suggest that L. japonica var. miyagusukiana is a local tetraploid derivative of the diploid L. japonica var. japonica in the Ryukyus. Because little information is available about the karyotype and phylogenetic features of L. japonica and its relatives, however, we cannot exclude the possibility that L. japonica var. miyagusuki- ana is derived from other diploid taxa found either in the Ryukyus or elsewhere.

Karyotypes of Ophiopogon reversus (Convallariaceae) collected from four localities in Taiwan and one locality on Yonaguni-jima Island in the southern Ryukyus of Japan were reported for the first time. Those of O. jaburan collected from three major islands (Amami-oshima, Tokuno-shima and Okinawa-jima) of the central Ryukyus were also investigated for comparison. All plants of O. reversus and O. jaburan investigated were diploid (2n = 36) based on the basic chromosome number of x = 18. Among 36 chromosomes of O. reversus, one pair of short chromosomes with submedian centromeres had secondary constrictions at the proximal region of the long arms. Based on this character, O. reversus is cytologically distinguishable from O. jaburan, in which one pair of short metacentric chromosomes had secondary constrictions at the proximal region of the short arms.

The proposed hybrid origin of Ixeris nakazonei collected in the Ryukyu Archipelago (Okinawajima) and the Atsumi Peninsula (Koijigahama) of central Japan was examined using nuclear DNA (nDNA) and chloroplast DNA (cpDNA) markers. The results indicated that most tetraploids of I. nakazonei (2n = 32) had nDNA of both putative parents, I. debilis (2n = 48) and I. repens (2n = 16). The first tetraploid of I. nakazonei must have arisen directly from interspecific hybridization between I. debilis and I. repens, considering the intermediacy of the chromosome number. All tetraploids on Okinawajima had cpDNA of I. repens, while those in the Atsumi Peninsula had cpDNA of I. debilis, indicating that the tetraploid has at least two independent origins. All hexaploids of I. nakazonei (2n = 48), on the other hand, had cpDNA of I. debilis, but some of the hexaploids had nDNA of both putative parents. Ixeris debilis and I. repens may also be involved in the origin of the hexaploid, although the establishment process of this cytotype is still obscure. Since the hexaploid of I. nakazonei is cytologically indistinguishable from I. debilis, it can backcross with I. debilis. Introgression from diploid I. repens to hexaploid I. debilis mediated by I. nakazonei possibly occurs on Okinawajima. © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 141, 379–387.

The time-course of the recovery of the hearing level after treatment in 90 patients with idiopathic sudden sensorineural hearing loss was examined. The improvement rate calculated relative to the hearing level of the opposite ear was investigated to estimate the hearing recovery. Follow-up audiograms were performed once per week for 1 month after treatment and once per month thereafter. There were two groups that differed with respect to the characteristics of hearing recovery. One group showed an improvement rate of over 50% at 1-2 weeks and a good improvement rate at 3 months after treatment. In the other group, the improvement rate did not reach 50% at 1-2 weeks, and the improvement rate was poor at 3 months after treatment. The patients with improvement rates of over 50% at 1-2 weeks had earlier initial visits and had mild hearing loss, whereas the patients with profound hearing loss had improvement rates under 50% and poor long-term prognosis. We conclude that the improvement rate at 1-2 weeks after treatment predicts the long-term prognosis for recovery of hearing level in patients with sudden sensorineural hearing loss.

In order to compare stand structure and woody species diversity of subtropical evergreen broadleaf forests along a latitudinal thermal gradient of the Ryukyu Archipelago, tree censuses in a 750 m2plot in Okinawa Island and a 400 m2plot in Ishigaki Island were performed. The number of layers increased along a latitudinal thermal gradient from four in the forest of Okinawa Island to five in the forest of Ishigaki Island. The values of Shannon’s indexH′ and Pielou’s indexJ′ tended to increase from the top layer downward in the forest of Okinawa Island, whereas in the forest of Ishigaki Island, these values tended to increase from the bottom layer upward. High woody species diversity depended on small-sized trees in the Okinawa forest, whereas it depended on large-sized trees in the Ishigaki forest. The woody species diversity is higher in the Okinawa forest (H′ = 4.83 bit) than in the Ishigaki forest (H′ = 4.36 bit). According to successively decreasing height of layers from the top downward, the value ofH′ increased continuously from the top layer downward in the Okinawa forest. This increasing trend was different from the Ishigaki forest, where the value ofH′ increased up to the second layer and then decreased downward. In the Okinawa forest, the expected number of species increased continuously from the top toward the bottom layer, i.e. the bottom layer contained the highest potential number of species (65). However, in the Ishigaki forest, it increased from the top to the fourth layer and then decreased to the bottom layer, i.e. the fourth layer contained the highest potential number of species (90). The floristic composition in the Okinawa forest was different from that in the Ishigaki forest in terms of similarity index, though approximately half of the species were common between them. The highest degree of similarity in floristic composition was between the second and third layers in the Okinawa forest, whereas it was between the third and bottom layers in the Ishigaki forest. The degree of similarity in floristic composition among layers was higher in the Okinawa forest than in the Ishigaki forest. Except the top and the bottom layer respectively in the forests of Okinawa Island and Ishigaki Island, the spatial distribution of trees was random in each layer. The degree of overlapping in the spatial distribution of trees among layers in these two forests suggested that trees in the upper two layers in the Ishigaki forest can catch sufficient light, while light can not penetrate easily to the lower three layers in both of the forests. As a result, almost species in the lower layers might be shade-tolerant in both of the forests. For both of the forests, mean tree weight of each layer decreased from the top downward, whereas the corresponding tree density increased from the top downward. This trend resembled the mean weight–density trajectory of self-thinning plant populations.

an endemic species occurring only along streams in the Yanbaru area in the north of Okinawa Island, the Ryukyus, is known to comprise di-, tri-, and tetraploids with x=13. Molecular analysis of chloroplast DNA sequences has shown that two haplotypes, AT- and NI-types, characterized by the insertion or deletion of four nucleotides “ATAT”, exist in E. suzukii. The AT-type was found in some diploids and triploids only at Genkagawa, whereas the NI-type is widespread, occurring in both diploids and triploids of the Genkagawa site as well as at other localities. The triploids share both types with the diploids, indicating that the triploids have at least two independent origins. Because of its restricted distribution, the AT-type triploid may have arisen within the Genkagawa area.

Although many people have expressed alarm that we are witnessing a mass extinction, few projections have been quantified, owing to limited availability of time-series data on threatened organisms, especially plants. To quantify the risk of extinction, we need to monitor changes in population size over time for as many species as possible. Here, we present the world's first quantitative projection of plant species loss at a national level, with stochastic simulations based on the results of population censuses of 1618 threatened plant taxa in 3574 map cells of ca. 100 km2. More than 500 lay botanists helped monitor those taxa in 1994-1995 and in 2003-2004. We projected that between 370 and 561 vascular plant taxa will go extinct in Japan during the next century if past trends of population decline continue. This extinction rate is approximately two to three times the global rate. Using time-series data, we show that existing national protected areas (PAs) covering ca. 7% of Japan will not adequately prevent population declines: even core PAs can protect at best

Aim Phylogeographical patterns in the Ryukyu Archipelago have been explained primarily by landbridge formation and the opening of two straits in the Pliocene, namely the Tokara and Kerama gaps. These old straits have been considered to be the barriers most likely to determine genetic boundaries. To test this, we conducted a molecular analysis of the herb Ophiorrhiza japonica. We discuss the causes of and processes involved in its phylogeographical structure and explore aspects of island separation other than the duration of the straits to explain genetic boundaries at the gaps. Location Ryukyu Archipelago, Japan. Methods Plants were collected from 40 localities in the archipelago and vicinity. Non-coding regions of chloroplast DNA were sequenced. The genealogical relationships among haplotypes were estimated using a statistical parsimony network. To examine the phylogeographical structure, we compared two parameters of population differentiation, namely GST and NST, and conducted correlation analysis of genetic and geographical distances. Genetic boundaries were identified using Monmonier’s maximum difference algorithm. To test vicariance–dispersal hypotheses, that is, vicariance after migration via the Pliocene landbridge or over-sea dispersal in the Pleistocene, molecular dating analysis was conducted. Results A statistical parsimony network revealed that the haplotypes from the Ryukyu Archipelago and northwards coalesce to one ancestral haplotype in Taiwan. A clear phylogeographical structure was observed: plants within the same population and populations in geographical proximity were phylogenetically close. A genetic boundary was recognized across the Kerama Gap, but not across the Tokara Gap. Dating analysis suggested that population divergence across the Kerama Gap occurred in the early to late Pleistocene. Main conclusions The statistical parsimony network suggests migration from Taiwan and northward range expansion in the archipelago. Based on the divergence time, over-sea dispersal in the Pleistocene is likely, although migration via a Pliocene landbridge is not totally rejected. Negligible genetic differentiation across the Tokara Gap suggests recent over-sea dispersal, possibly facilitated by the small geographical width of the gap. Conversely, the large genetic differentiation across the Kerama Gap is probably explained by the large geographical distance across it. The past splitting of a landbridge would have had a significant influence on population differentiation after a certain geographical distance was reached.

Molecular phylogenetic analyses, morphological observations, and nomenclatural studies were carried out to investigate the taxonomic status of Portulaca boninensis, endemic species from the Bonin (Ogasawara) Islands (Japan). The results addressed controversy between the widely naturalized P. boninensis and P. pilosa, indicating that they are phylogenetically and morphologically distinct. Furthermore, P. boninensis was showed to be conspecific to P. psammotropha which is until now recorded in southern China, Taiwan, and the northern Philippines, but not in the Ryukyus. The name of P. psammotropha was lectotypified on a specimen preserved at K. Based on phylogeography, P. psammotropha likely migrated to the Oceanic Bonin Islands oversea by sea-current dispersal or by exo- and/or end ozoochory through migratory birds without passing through Ryukyus.

We examined the floral morph of tetraploid Ophiorrhiza japonica Blume var. amamiana Hatus. and diploid O. japonica var. japonica to elucidate the association of distyly and ploidy levels. Chloroplast DNA phylogeny was reconstructed to determine the number of tetraploidization events and floral morph shifts in O. japonica. All individuals of O. japonica var. amamiana proved to be long-homostylous, whereas O. japonica var. japonica was distylous with typical long- and short-styled flowers. Distyly is related to the ploidy level. The bagging treatment of flowers indicated that O. japonica var. amamiana is self-compatible and potentially automatically self-pollinating. In cpDNA sequencing analysis, no haplotype was shared between the two varieties. The cpDNA haplotype network displayed the monophyly of O. japonica var. amamiana, suggesting a single origin of this variety. Hence, both tetraploidization and the breakdown of distyly to homostyly in O. japonica var. amamiana likely occurred just once. Because O. japonica var. amamiana having the morphological and cytological entity is recognized as a single lineage and clearly separated from O. japonica var. japonica, this variety can be considered to be a distinct species. We therefore propose to raise O. japonica var. amamiana to the rank of species.

Hayataella (Rubiaceae) is a monotypic genus endemic to Taiwan that comprises H. michelloides. In recent years, Hayataella was considered to be synonymous with Ophiorrhiza; however, no specific data have been reported, and the systematic treatment of Hayataella has been unclear. To elucidate the systematic treatment of Hayataella, molecular phylogenetic analyses based on ITS of nrDNA, atpB–rbcL, and trnK/matK of cpDNA were conducted with four Ophiorrhiza species. In the Bayesian and the most parsimonious trees, H. michelloides was included in the Ophiorrhiza clade. The monotypic status of Hayataella is, therefore, not considered appropriate, and the combination Ophiorrhiza michelloides (Masam.) H. S. Lo is supported.

The cytogeographical structures of Ixeris nakazonei, a putative hybrid between I. debilis (6x) and I. repens (2x), were investigated in the Ryukyu Archipelago and Taiwan. In the Ryukyus, I. debilis occurs on Miyakojima Island of the southern Ryukyus and northward, while I. repens occurs on all islands except for Iriomotejima and Yonagunijima Islands. I. nakazonei, comprises six polyploid cytotypes, 3x, 4x, 5x, 6x, 7x and 8x, based on x=8. Four cytotypes from 3x to 6x occur in the central Ryukyus, while four cytotypes from 5x to 8x occur in the southern Ryukyus. The higher polyploids of I. nakazonei tend to be distributed in the more southerly area. Tetraploids of I. nakazonei always co-occur with I. debilis and I. repens, supporting the hybrid origin of this cytotype. Considering the chromosome number, octoploids, which predominate in the southern Ryukyus and Taiwan, may have derived directly from hybridization between I. debilis and I. repens. Odd-numbered polyploids of I. nakazonei, 3x, 5x and 7x, are relatively rare. Their chromosome numbers indicate that triploids and heptaploids are hybrids between the tetraploid of I. nakazonei and I. repens, and between the octoploid of I. nakazonei and I. debilis, respectively. Pentaploids of I. nakazonei in the central and southern Ryukyus are, respectively, hybrids between the tetraploid of I. nakazonei and I. debilis and between the octoploid of I. nakazonei and I. repens, indicating that pentaploids of I. nakazonei have at least two independent origins.

Magnetic resonance (MR) images of 62 patients with tinnitus were reviewed. These included T 1 -weighted and T 2 -weighted axial images and three-dimensional spoiled gradient-recalled acquisition in steady-state (3D-SPGR) imaging with gadopentetate dimeglumine. In 49 cases with tinnitus occurring gradually, the MR images of 2 cases (4.1%) suggested arterial dissection of the vertebrobasilar system. One of these patients underwent vertebral angiography (VAG) and no dissection was confirmed. In 13 cases of sudden-onset tinnitus, MR images of 3 cases (23.1%) suggested arterial dissection. Of these three cases, VAG was performed in two, resulting in arterial dissections being confirmed in two cases. It was concluded that the arterial dissection of the vertebrobasilar system was one of the causes of sudden-onset tinnitus. Abnormalities in neurotological examinations in cases with tinnitus caused by the arterial dissection of vertebrobasilar system implied that the tinnitus was caused by inner ear dysfunction.

The absence of the cosmopolitan genus Limonium Miller (1754: no pagination) (Plumbaginaceae) in the mega-diverse flora of the Malesian region (comprising Brunei Darussalam, Indonesia, Malaysia, Papua New Guinea, the Philippines, and Singapore; Merrill 1923, Ridley 1923, Steenis 1949, Backer & Bakhuizen van den Brink Jr. 1965, Balgooy 1993, Coode et al. 1996, Balgooy 2001, Conn et al. 2004, Chong et al. 2009, Pelser et al. 2011) has intrigued taxonomists and biogeographers since Steenis (1949) noted this. During a field survey as part of the project on floristic and phylogenetic biogeography in the island chain of the Philippines, Taiwan, and southern Japan, we found a population of Limonium in the northern Philippines (Batan Islands) that represents the first record of the genus in the Malesian region. Batan Islands, comprising 10 small (≤ 83.1 km2) oceanic islands, is the northernmost tip of the Malesian region, being ca. 190 km north of Luzon Island of the Philippines and ca. 140 km southeast of Taiwan Island. From the geological location, the present finding suggests that a more extensive survey in Batan Islands may add some more East Asian temperate genera to the flora of the Malesian region, although two enumerations of the early and mid 20th century provide us baseline knowledge of the flora of Batan Islands (Merrill 1908, Hatusima 1966).

We used molecular phylogenetic and morphological data to reexamine the taxonomic status of Portulaca okinawensis (≡ P. pilosa subsp. okinawensis ) endemic to the central Ryukyu islands, southwestern Japan. Our molecular analyses showed that P. okinawensis is monophyletic, sister to the clade of P. psammotropha and P. tuberosa and it is not closely related to P. pilosa subsp. pilosa . Two subclades, one comprising plants from the Okinawa Islands and the other from the Amami Islands, were recognized. The plants from the Okinawa Islands had more than 20 stamens, orange-yellow nallowly obovate to oblanceolate petals, and reddish-green stems (as the holotype), while the plants from the Amami Islands had less than 20 stamens, lemon-colored obovate petals, and bright-green stems. The molecular and morphological data support a taxonomic treatment of Walker & Tawada (1951) regarding P. okinawensis as a separate species, also suggesting that the plants from the Amami and Okinawa islands should be treated as different taxa. A new variety Portulaca okinawensis var. amamiensis was here described.

Morphological comparisons and molecular phylogenetic analyses were conducted to resolve taxonomic confusion in Cassytha glabella and C. pubescens, both of which were first described from Australia and subsequently considered to be disjunctly distributed between Australia and the Ryukyu Archipelago of Japan. In the morphological comparisons, plants considered as C. pubescens in the Ryukyus differ from C. pubescens in Australia in the presence or absence of hairs on the petals, and those considered as C. glabella in the Ryukyus differ from the C. glabella in Australia in bract and peduncle morphology. The molecular analyses indicated that plants attributed to C. pubescens in the Ryukyus were not closely related to C. pubescens in Australia, and were nested in a clade of populations of a Pan-Western Pacific species C. filiformis. Plants attributed to C. glabella in the Ryukyus were distantly related to C. glabella in Australia. We concluded that plants considered as C. pubescens and C. glabella in the Ryukyus are to be respectively treated as C. filiformis and the Ryukyu endemic species C. pergracilis.

We tested the antitropical distribution of Lobelia loochooensis, endemic to the Ryukyu Archipelago of Japan, and its putative sister species of the same section Hypsela in Oceania (Australia and New Zealand). Molecular phylogenetic analyses based on cpDNA sequences were conducted for 41 Lobelia species of 11 sections including all the species of sect. Hypsela investigated in Asia and Malesia and 32 species of 16 allied genera of family Campanulaceae, because the genus Lobelia is known to be polyphyletic. In the result, L. loochooensis and an Australian endemic L. fluviatilis formed a clade, and this clade was sister to a clade of four New Zealand endemics: L. carens, L. fatiscens, L. fugax and L. ionantha. These two clades were nested in a clade with two other Australian congeners. We conclude that: (1) the lineage of L. loochooensis and the five Lobelia species occurring in Oceania demonstrate an antitropical distribution pattern; and (2) L. loochooensis has likely originated from a dispersal event from Australia to the Ryukyu Archipelago.

The genus Oxygyne comprises three species disjunctly distributed in Africa and Japan and is the least examined genus of the Burmanniaceae due to the scarcity of living material. We obtained living samples of Oxygyne shinzatoi and examined the phylogenetic position of this species on the basis on the 18S rDNA sequence. Oxygne shinzatoi was consistently found to belong to the monophyletic group of tribe Thismieae, but its position in the tribe differed depending on the criteria applied (maximum parsimony, maximum likelihood, Bayesian inference). Distance analysis from the most recent common ancestor indicated that O. shinzatoi had the lowest substitution rate among the species of tribe Thismieae. Combined with recent knowledge of basic chromosome numbers and substitution rate characteristics, O. shinzatoi can be considered to be one of the basal taxon of tribe Thismieae.

Viola stoloniflora Yokota et Higa (Violaceae) is newly described from Okinawa Island, the Ryukyus. This species is characterized by the procumbent stolons, the almost round leaf blades, the densely pilose petioles, the ebarbate white petals with violet veins, and the chromosome number of 2n=22. The present species belongs to Sect.Nomimium, Subsect.Serpentes and is closely related to theV. iwagawai group of Sect.Nomimium, Subsect.Adnatae.