百原 新

A latest Pliocene (2.6 Ma) wetland forest vegetation that was dominated by Glyptostrobus and Metasequoia was reconstructed from in situ woods, fruits and seeds, and pollen assemblages in deposits of the Kobiwako Group exposed in the Yasu River, Shiga Prefecture, central Japan. Based on species composition of stumps and autochthonous plant macrofossil assemblages in the fossil forest beds and their sedimentological assessments, habitat partitioning of Glyptostrobus and Metasequoia was clarified. The forest floor of Glyptostrobus dominant stands were covered by wetland plants, including Cyperaceae and submersed herbs. Size class distribution of stumps indicates that Glyptostrobus regenerated continuously and grew over a long period of time in a stable environment in a water-logged backmarsh. Metasequoia dominant stands were established in environments drier than those dominated by Glyptostrobus, and were accompanied by forest floor herbs and shrubs with mesic habit preferences. The upland forest vegetation reconstructed from allochthonous assemblages in sandy channel-fill deposits was mixed coniferous and deciduous broadleaved tree forest that was dominated by Picea, and included trees now extinct in Japan, such as Sequoia, Cunninghamia, Cyclocatya, and Fagus microcarpa. Sciadopitys and Cathaya, represented only by pollen, grew on mountain slopes and ridges away from the river. Their habitats did not extend to backmarshes in the lowlands during the Neogene and the Early Pleistocene in East Asia. Paleotemperature reconstructed from plant macrofossil assemblages indicates the temperature conditions typical of the lower boundary of the cool temperate deciduous broadleaved forest zone. The occurrence of Glyptostrobus and Metasequoia in another fossil forest in the Early Pleistocene (1.8-1.9 Ma) in the same sedimentary basin demonstrates their tolerance to cool-temperate climates. (C) 2015 Elsevier B.V. All rights reserved.

Several terrestrial plant fossils found in the late Cenozoic of Europe belong to thermophilous genera or infrageneric taxa which do not grow in this continent today, and are usually called "exotic elements". Within this large group we singled out three more precisely defined categories based on the hypothesis that the change of geographic distribution between the late Cenozoic and the present is the result of deterministic extinctions caused by climate change. Among the taxa shared by the modern East Asian and the Plio-Pleistocene European flora, the "humid thermophilous taxa of East Asian affinity" (HUTEA) represent the central category in our study. These were traditionally considered "Pliocene" elements in Europe. In our analysis of 13 reliably dated Italian assemblages the percentage of species belonging to the HUTEA category was found to be higher in Pliocene sites, and very low to null in Pleistocene ones. Also early Pleistocene assemblages across all of Europe did not contain any HUTEA, apart from Eucommia, and Symplocos sect. Lodhra in the refugial area of the Colchis. Our analysis of fruit and seed assemblages in the San Lazzaro section (Umbria, central Italy), recently assigned to the early Pleistocene, provided contrasting evidence, which required a reconsideration of the stratigraphic and palaeontological context of another well known site in central Italy, Cava Toppetti II. Using vertebrate and continental mollusc biochronology the early Pleistocene age of this section was confirmed and its palaeontological records were compared with other assemblages in central Italy and Europe. We show that in central Italy at least three HUTEA species (Sinomenium cantalense, Symplocos casparyi, Toddalia rhenana) persisted after the Pliocene/Pleistocene boundary. We conclude that central-southern Italy offered a refugial niche that was warm and wet enough to assure the longer survival of some HUTEA, in contrast to central Europe. (C) 2015 Elsevier B.V. All rights reserved.

Based on organelle DNA phylogeographic analyses and ecological niche modeling (ENM), we investigated the range-shift history of the Japanese wingnut (Pterocarya rhoifolia) during the Quaternary climatic oscillations with particular emphasis on the Last Glacial Maximum (LGM). Phylogeographic patterns of this species were determined using 376 individuals from 53 populations for chloroplast DNA sequencing of three spacers. Spatial analysis of molecular variance revealed that the current phylogeographic structure would be sculptured by multiple range shifts from each glacial refugium, which would have been repeated several times during the Quaternary climatic oscillations. High haplotype diversity and private haplotypes were detected in southwestern Japan, where wingnut is currently infrequent and found mainly in high mountains, whereas in northernmost Japan, haplotype diversity was low though this plant is quite common at present. According to ENM approach, during the LGM, the climatically suitable distribution areas were not recovered in northeastern Japan but in lowlands of southwestern Japan. Our combined results suggest that Japanese wingnut primarily persisted in the lowlands of southwestern Japan and coastlines below 36.5 degrees N latitude during the LGM, having led to the postglacial range expansion from the refugia in each area of southwestern and lower latitudinal northeastern Japan, and to the wide-range recolonization from the southerly refugium/refugia to the north in northernmost Japan. The southwestern and coastal refugia have played a role in shaping the current haplotype diversity and phylogeographic structure, whereas some rear edge populations, harboring unique haplotypes, have been also maintained.

<p>中部日本とその周辺の鮮新・更新世の地形発達が植物相と植生の変遷に与えた影響について総説した．下部更新統菖蒲谷層ではメタセコイアが氷期の化石群にも含まれていることから，メタセコイアの日本からの絶滅要因として気候よりむしろ生育場所の地形の変化が考えられた．近畿地方中部では植物の絶滅と冷温帯の植物群の出現の時期が，堆積盆地周辺の古地形の変化と良く対応していた．これらのことを検証するために，堆積盆地周辺の古地形に対応した植物の分布を，植物化石群の形成過程を考慮して復元した．日本からの植物の絶滅は，山地形成によって間氷期の植物の分布拡大が妨げられたことで，植物の分布域が西南日本へと縮小していった結果生じたと考えられる．植物の分布は，乾燥気候が卓越した最終氷期最寒冷期には，気温条件だけではなく土壌水分条件にも制限された．乾燥した立地を中心に亜高山帯針葉樹が冷温帯に分布を拡大した一方で，温帯落葉広葉樹の分布は谷の中の中湿立地に限定された．</p>

This study investigated the influence of sea-level and climate changes on the decreased fluvial aggradation and subsequent widespread peat initiation in the middle to late-Holocene in the Ishikari lowland, which is a coastal floodplain formed in response to the postglacial sea-level change. By introducing a new approach to separately evaluate the rates of organic and clastic sediment input, we demonstrated that the peat began to form when the fluvial sedimentation rate was significantly decreased (less than 0.6 mm/yr), while plant macrofossil analysis suggested that lowering of water level is also important to the peat initiation. Such changes in sedimentary environment may be associated with the abrupt abandonment of crevasse splays. The concentrated ages of the peat initiation around 5600-5000, 4600-4300, and 4100-3600 cal. BP suggest that an allogenic control promoted the abandonment of crevasse splays, and different onset ages can be explained by different fluvial responses of the Ishikari River and its tributaries. The abandonment of crevasse splays could result from sea-level fall or decreased precipitation. While submillennial sea-level fluctuations coincident with the peat initiation have not been reported in coastal lowlands of Japan, the close comparison of the onset ages and decreased precipitation recorded in a stalagmite from China, which represents the strength of the East Asian summer monsoon (EASM), suggests that decrease in precipitation led to the abandonment of crevasse splays. Our results may indicate that similar fluvial responses might be common in other coastal floodplains affected by the EASM.

Paleovegetation and climatic conditions in the Last Glacial Maximum (LGM; ca. 24.4 and 20.1 ka) were reconstructed based on plant macrofossils and pollen assemblages deposited in a sandy channel out-cropped in the Hanamuro River, Ibaraki Prefecture, central Japan. The plant macrofossil assemblages were composed of 31 arboreal and 76 herbaceous taxa. Occurrence of plants with various habitat preferences exhibited distribution patterns of highly diverse vegetation types depending on geo-morphology and humidity in and around the drainage of the Hanamuro River. Rich aquatic and wetland flora indicates an expansion of backmarsh mosaic environments along the river channel in the bottom of the valley. Wetland forests composed of Picea sect. Picea assignable to Picea koyamae, and riparian forests dominated by Alnus inokumae, are well represented in the macrofossil assemblages. Pinaceous conifers were dominant in mesic or dry places with Betula and the other deciduous broadleaved trees. Macrofossils and pollen indicates that Abies veitchii was distributed in mesic locations, Larix kaempferi and Picea jezoensis var. hondoensis were on the upper slopes, and Pinus koraiensis was dominant on the plateau. Dominant Selaginella remotifolia and the other drought-intolerant understory herbs indicate closed canopy of mesic coniferous forests, while many kinds of meadow and/or ruderal plants were indicative of open vegetation along the river and slopes. Annual mean temperature of the fossil site based on occurrence of Selaginella remotifolia was 8.1 degrees C, which is observed in present cool temperate zones where deciduous broad-leaved trees are dominant. This indicates that the distribution limit of subarctic conifers shifted to warmer temperature conditions than at present. The overlapping distribution of temperate and subarctic plants occurred widely in the lowlands in the distribution ranges of temperate trees, south of around 38 degrees N in Japan. In the LGM, with lower precipitation, dryness was an important environmental factor that controlled plant distribution along with temperature. Water stress confined temperate broadleaved trees to the humid valley bottoms and relieved conifers from competition against broad-leaved trees to promote their expansion to warmer regions. Macrofossils indicate the persistence of temperate plants in humid inland and/or northern refugia during the LGM, locations conducive to Paleolithic human occupation. (C) 2016 Elsevier Ltd and INQUA. All rights reserved.

Gametophytes of epiphytic and epipetric pteridophytes occur frequently in bryophyte colonies; however, little is known about the influence of bryophytes on pteridophyte establishment. In the present study, we describe how the spore-holding capacity of bryophyte colonies contributes to the retention of pteridophyte spores in a vertical environment. Lycophytes did not grow at the sampling site; hence, we used Lycopodium spores to distinguish from any other pteridophyte spores that might have already been present in the wild. We dispersed aliquots of approximately 500,000 spores on vertically suspended bryophyte (both mosses and liverworts) colonies (5 cm X 5 cm) attached to ceramic plates. The bryophyte colonies included ten species (seven mosses and three liverworts), which have different characteristics in colony height, leaf length, and dry weight. Mudstone blocks and ceramic plates were used as control surfaces (5 cm X 5 cm). After simulated rainfall, we counted the number of spores retained in the colonies and controls. We found that the bryophyte colonies retained a significantly higher percentage of Lycopodium spores (90.7 +/- 7.4%) than the controls (ceramic plate: 7.5 +/- 20.9%; mudstone: 39.7 +/- 20.6%). The average values of retained spores within the bryophyte colonies correlated with their logarithmic values of dry weight per square centimeter (R-2 = 0.62, P < 0.05). Leaf thickness and stem diameter were slightly different across species. Thus, dry weight value of bryophyte colony per unit area is very likely a simple function of number of stem-and-leaf units, which correlate closely with the surface area. Bryophyte colonies that have high surface area on which pteridophyte spores might be retained within a colony might provide a suitable environment for spore adherence in epiphytic and epipetric habitats.

Late Quaternary plant macrofossils from fluvial, fluvio-deltaic and lacustrine sediments of the Golcarna Formation in the Besigaon, Mulpani, and Dhapasi sections in the Kathmandu Valley, Nepal were analyzed. The obtained plant macrofossils allowed us to reconstruct the late Pleistocene paleoenvironment in central Nepal, which was influenced strongly by the SW Indian monsoon system and tectonic movements of the Himalayas. In total, 102 taxa from 52 families were identified to genus or species levels. The dominance of Eurya, Ficus, Moms, Zizyphus, Stephania, Rubus, Quercus subgen. Cyclobalanopsis, Pyracantha, and Carpinus in the lower and middle plant macrofossil assemblages indicates influence of a warm climate. In the upper plant macrofossil assemblages, the higher contents of cooler climatic taxa such as Abies, Pinus, Picea smithiana, Tsuga dumosa, Taxus wallichiana, Quercus subgen. Lepidobalanus, and Betula indicate a climatic deterioration. The higher diversity and common occurrence of aquatic plants indicate rich wetland vegetation in the Kathmandu basin. The plant macrofossil analysis shows at least three cycles of climate fluctuation between warm and cool phases during the deposition of the Golcarna Formation between 53,170 +/- 820 yrs. BP and 49,300 +/- 2100/1700 yrs. BP. These cycles seem to be fairly local or regional, but this can also be correlated with the overall global cooling context in GISP2 oxygen isotope curve in the late Pleistocene. (C) 2016 Elsevier B.V. All rights reserved.

In the present study, the plant macrofossil stratigraphy of the Plio-Pleistocene sedimentary basins of Japan is reviewed, and the process of development of modern flora is discussed. Taxa endemic to the modern flora of central and south China became extinct, while plants that have been dominant in the recent cool-temperate and subarctic zones of Japan increased and/or emerged after the Late Pliocene. The floral change was stepwise, and the events were concentrated in transition periods of climatic fluctuation and/or in a downward shift of the glacial climate. These events are represented by the last occurrence of exotic taxa at 3.35 Ma, 2.9 Ma, 2.7-2.5 Ma, 1.2 Ma, 0.9 Ma, 0.5 Ma, and in the Late Pleistocene. Local extinctions occurred earlier in northern and inland basins, and the first appearance of plants dominant in modern cool-temperate and subarctic forests was dependent on the topography of mountains surrounding the basin. Geomorphological changes that were accompanied by mountain uplifts and sea level changes occurred in and around sedimentary basins during stage of floral changes. These alterations, along with climate changes, likely changed the habitats and migration routes of plants, which ultimately resulted in their extinction. (C) 2015 Elsevier Ltd and INQUA. All rights reserved.

This paper reviews recent archaeobotanical evidence of the beginnings of rice and millet agriculture in prehistoric Japan, focusing on agricultural weed assemblages from early rice cultivation sites. In this study we show that the most reliable dispersal timing of rice and millet cultivation was the end of the Final Jomon period, corresponding to the Initial and Early Yayoi period of northern Kyushu. Rice and millet were introduced from China via Korea probably at the same time, as a pair. Early rice cultivation was likely practiced, not in slash-and-burn fields but in primitive paddy fields, which did not possess clearly defined paddy ridges or compartments, and were constructed in human-managed open wetlands near forests. Millets were probably cultivated on upland farmlands close to rice paddy fields. The use of berries and nuts which was the subsistence base of Jomon period continued during this time, and rice and millet agriculture gradually spread up until the Middle to Late Yayoi period. (C) 2015 Elsevier Ltd and INQUA. All rights reserved.

Owing to the existence of global Pleistocene refugia, the relict and ancient component of the modern endemic flora is considerable in South-Central China. Study of these relict species helps to understand past and recent ecological processes affecting species persistence, and also provides knowledge to guide human-assisted management and conservation practice. In this study, we investigated the current status of the remnant populations of Cathaya argyrophylla, one of the emblematic "living fossils", growing in the Dalou Mountains of South-Central China. We quantified the population structure of C. argyrophylla and investigated demographic changes of seedlings over a ten year period to learn the plant's regeneration patterns following the establishment of two national and provincial nature reserves in late 1970s. Notable "gaps" in age structure over 40 years were found, suggesting significant recruitment failures in these scattered population since the establishment of the nature reserves. Further, the number of dead individuals peaked at ages between 40 and 80 years and the seedlings showed high mortality in the past 10 years, probably due to intensified competition from the nearby broad-leaved trees and the reduction of suitable micro-habitats. These facts indicated that attention needs to be paid and follow-up measures should be taken to more effectively conserve C. argyrophylla in the future. (C) 2015 Elsevier B.V. All rights reserved.

日本列島における「弥生の小海退」は，その存在が認められる地域と認められない地域が明確になっておらず，その存在が報告された地域においても，海水準インデックス・ポイントが連続的に得られていないことに問題がある．筆者らは，利根川低地最奥部において，水深が約1～2mと推定され，3～2cal kyr BPの海水準上昇に伴って形成されたと考えられる湖沼堆積物を発見した．その堆積年代と分布深度は，水深を推定値の最大の2mと仮定しても，海水準が3.0cal kyr BPには標高-2.2mまで低下したことを示す．この低下量は予想される圧密の総和よりも大きく，また，周辺では大規模なテクトニックな地殻変動は考えにくい．したがって，この事象は利根川低地最奥部に「弥生の小海退」が存在したことを意味する．このような相対的海水準低下の要因としては堆積物荷重の影響を今後最も検討しなければならない．

1. ロシア沿海地方最南部ウスリー川源流域でチョウセンヒメバラモミ－チョウセンゴヨウ－落葉広葉樹混交林の土壌乾湿分布を調査し，その結果から中部日本山岳域の最終氷期以来の植生変遷を展望した．<br>2. 土壌乾湿傾度に沿って，乾性から中湿性立地ではモンゴリナラが優占し，イタヤカエデ，ヤエガワカンバ，ときにアムールシナノキが混在する落葉広葉樹林に，チョウセンゴヨウが混生，チョウセンヒメバラモミも点在分布するタイプの林分が分布していた．中湿性から湿潤立地ではチョウセンヒメバラモミが優占し，チョウセンゴヨウが混在する針葉樹林に，イタヤカエデ，アムールシナノキ，ときにチョウセンミネバリが混在するチョウセンヒメバラモミ－チョウセンゴヨウ－落葉広葉樹混交林が成立していた．最も湿潤な立地ではドロヤナギ，ハルニレ，ヤチダモを主体とし，チョウセンヒメバラモミが散在する，よく発達した河畔林が成立していた．チョウセンヒメバラモミ－チョウセンゴヨウ－落葉広葉樹混交林全体としては乾性立地よりも中湿性から湿潤立地がより適した分布地といえる．<br>3. 沿海地方のチョウセンヒメバラモミの土壌乾湿分布から，バラモミ節樹木は最終氷期時には，現在の分布とは異なり，斜面中・下部から渓流域の河岸段丘や氾濫原に分布の本拠があった可能性が高い．チョウセンゴヨウは，チョウセンヒメバラモミと比べると，やや乾性な立地が分布適域であった．<br>4. 中部日本の植生変遷を展望すると，最終氷期には，低地・低山帯では，大陸型の亜寒帯性針葉樹林要素とされたバラモミ節樹木，チョウセンゴヨウが，実際には，中湿性から湿潤立地を中心に，異なる落葉広葉樹と混交しながら冷温帯林を構成していた．山地帯の乾性から中湿性立地には現在とほぼ同じ構成のトウヒ，シラベ，コメツガ，時にバラモミ節樹木，チョウセンゴヨウを含む常緑針葉樹疎林が分布していた．湿潤立地にはハイマツ低木林やダケカンバ林，オオシラビソ小林分などが点在していた．これは現在のシホテ－アリニ山脈の垂直分布と類似しており，現存する植生垂直分布と整合している．<br>5. 後氷期には湿潤，多雪化で土壌形成が進み，バラモミ節樹木やチョウセンゴヨウは亜高山帯の岩礫地に追いやられた．とりわけ，バラモミ節樹木の衰退には多雪化が大きく影響した可能性がある．かわって山地帯では立地ごとに異なる落葉広葉樹林が低地・低山帯から広がった．<br>6. バラモミ節樹木やチョウセンゴヨウが分布する立地は大型植物化石が堆積・残存しやすく，そのために産出量も多くなる．一方，トウヒ，シラベ，コメツガが分布していた立地は大型植物化石が堆積しにくく，そのために産出量も少ないと考えられる．このことから直ちに，トウヒ，シラベ，コメツガが最終氷期当時，現在よりも分布量が少なかったとみなすことは危険である．

Ferns typically grow in soil that has sufficient moisture to enable the germination, fertilization and growth of gametophytes. However, the epiphytic fern, Lepisorus thunbergianus grows on tree trunks often in urban areas, where its gametophytes are susceptible to desiccation and its spores are easily washed off by rainwater. To understand how these ferns become established and survive in such challenging conditions, we conducted a quadrat survey on trunks of Prunus mume (which has cracked bark) and Ilex integra (which has smooth bark), focusing on the presence of bryophyte communities, which are known to facilitate seed establishment. Regardless of bark roughness, fern gametophytes occurred more frequently in the communities of small-leaved and short-bodied liverworts, and young fern sporophytes occurred more frequently in the communities of tall-bodied mosses. As the gametophytes of L. thunbergianus are taller than the liverworts, they are able to grow in the presence of liverworts without experiencing shading effects. However, sites with liverworts were unsuitable for fertilization of fern gametophytes because they were more desiccative environments than the sites where tall mosses grew. In habitats where tall mosses grow, fern gametophytes tended to be affected by competition from the bryophytes, whereas once fern gametophytes had established and matured, it was easy for them to generate young sporophytes because tall mosses retain sufficient moisture for the ferns' fertilization. In summary, the presence of a moss community is an important factor aiding the establishment of this epiphytic fern in desiccated urban areas.

The change in ancient atmospheric CO2 concentrations provides important clues for understanding the relationship between the atmospheric CO2 concentration and global temperature. However, the lack of CO2 evolution curves estimated from a single terrestrial proxy prevents the understanding of climatic and environmental impacts due to variations in data. Thus, based on the stomatal index of fossilized Metasequoia needles, we reconstructed a history of atmospheric CO2 concentrations from middle Miocene to late Early Pleistocene when the climate changed dramatically. According to this research, atmospheric CO2 concentration was stabile around 330-350 ppmv in the middle and late Miocene, then it decreased to 278-284 ppmv during the Late Pliocene and to 277-279 ppmv during the Early Pleistocene, which was almost the same range as in preindustrial time. According to former research, this is a time when global temperature decreased sharply. Our results also indicated that from middle Miocene to Pleistocene, global CO2 level decreased by more than 50 ppmv, which may suggest that CO2 decrease and temperature decrease are coupled.

A rare coniferous Tertiary relict tree species, Thuja sutchuenensis Franch, has survived in the Daba Mountains of southwestern China. It was almost eliminated by logging during the past century. We measured size and age structures and interpreted regeneration dynamics of stands of the species in a variety of topographic contexts and community associations. Forest communities containing T. sutchuenensis were of three types: (1) the Thuja community dominated by T. sutchuenensis, growing on cliffs; (2) the Thuja-Quercus-Cyclobalanopsis community dominated by T. sutchuenensis, Quercus engleriana and Cyclobalanopsis oxyodon, along with Fagus engleriana and Carpinus fargesiana, on steep slopes; (3) the Thuja-Tsuga-Quercus community dominated by T. sutchuenensis, Tsuga chinensis, and Quercus spinosa, on crest ridges. The established seedlings/saplings were found in limestone crevices, on scarred cliff-faces, cliff-edges, fallen logs, canopy gaps and forest margins. The radial growth rate was 0.5-1.1 mm per year. Its growth forms were distorted. It had strong sprouting ability after disturbances. The T. sutchuenensis population thrives on cliffs where there is little competition from other species because of harsh conditions and rock-slide disturbances. It is shade-intolerant but stress-tolerant. Its regeneration has depended on natural disturbances.

Gleditsia japonica Miq. (Leguminosae) is an endangered species in some prefectures of Japan. We classified the habitats of G. japonica into the following three types and compared the variation in regeneration traits among these habitats: (1) stream banks of the upper reaches of rivers, (2) drained terraces in the riverbeds of the middle and lower reaches of rivers, and (3) non-riparian habitats such as shrines, graves, and roadsides. The diameter at breast height (DBH) of trees thriving in riparian habitats was smaller than that of trees growing in non-riparian habitats. This finding suggests that riverside populations are frequently regenerated by disturbances. In the upper reaches of rivers with closed canopies, the DBH did not highly vary within a population, and very small number of seedlings was found. These data suggest that a G. japonica population might regenerate from seedlings immediately after a disturbance in the site. Thereafter, under low light condition, it might be difficult for the seedlings of G. japonica to grow; however, regeneration occurs via the root suckers to maintain the population. On the other hand, in the middle and lower reaches of rivers with discontinuous canopy, G. japonica showed a wider range of DBH and produced abundant seedlings and saplings. These observations suggest that G. japonica could be continuously regenerated through seeds under high light conditions, which might occur due to river flooding.

宇都宮市北部中里の丘陵の埋積谷中の堆積物（約20,300〜16,600calBP）に含まれる花粉化石と大型植物化石から，最終氷期最寒冷期（LGM）〜晩氷期初期の古植生を復元した．当時の調査地付近の丘陵には，トウヒやコメツガ，シラビソ，ダケカンバといった現在の本州中部の亜高山帯針葉樹林の優占種に，温帯性落葉広葉樹のオオモミジ，イタヤカエデ，サクラ属が混じって生育していた．約18,800calBP以降，LGMの終了と共にマツ科針葉樹が減少し，落葉広葉樹のカバノキ属，クマシデ属-アサダ属，ニレ属-ケヤキ属，カエデ属，シナノキ属が増加した．関東地方とその周辺のLGMの化石群の組成と標高・立地環境の関係に基づくと，現在の亜高山帯針葉樹林の優占種から主に構成される中里の化石群は，丘陵から山地域の森林の種組成を反映している．一方，LGMの化石群で産出頻度の高いトウヒ属バラモミ節，カラマツ属，チョウセンゴヨウは，低地の湿地林とその周辺で落葉広葉樹と混交していた．

近年，圧痕法の進展により，水洗選別によって得られた植物資料と，土器圧痕として検出された資料の組成には差異があることが指摘され始め，遺跡本来の植物利用や周辺の植物相を把握するためには，植物遺体のみでなく圧痕資料も加味する必要性があると意識され始めた。本稿は，下宅部遺跡出土の縄文土器の圧痕調査を行ない，本遺跡で利用された植物を土器圧痕から検討したものである。また，下宅部遺跡に近接し，同時期の遺跡と評価されている日向北遺跡についても土器圧痕調査を行ない，低湿地遺跡と低湿地から離れた台地上の遺跡という立地の異なる遺跡間での圧痕資料の組成を比較した。その結果，両遺跡においても植物遺体として検出された大型植物種実よりも小型の植物種実を圧痕として検出することができた。また，下宅部遺跡では植物遺体では確認されていない時期のダイズ属圧痕を確認し，縄文時代中期中葉～後期中葉の間は連続的にマメ科植物が利用されていたことを明らかにした。下宅部遺跡と日向北遺跡では一致した資料がなく，両遺跡の有意的な関係性は読み取れなかった。また，下宅部遺跡では注口土器の把手接合部からダイズ属子葉がみつかり，意図的な混入の可能性が示唆された。圧痕混入の意図についてはまだ十分な議論が必要であるが，このような圧痕資料の特殊な傾向が明らかになってきたのは，最近の土器圧痕調査の進展による成果といえよう。今回の検討でも，遺跡全体における利用植物の実態把握には複数の回収法によって得られた資料間の比較が重要であること，それらの資料から総合的に利用植物を判断する作業が必要であることを追認した。

The fossil pollen records from Koda Mire in the Kochi Plain, Shikoku, southwestern Japan, provide a vegetation history surrounding the mire during the full glacial and early post-glacial periods. Based on distribution patterns from representative pollen taxa, three local pollen assemblage zones (KD-I to KD-III) have been identified. The forest vegetation is characterized by the dominance of Quercus subgenus Quercus combined with Tsuga sieboldii, Carpinus, Fagus crenata, Betula, Acer and Corylus (KD-I: ca. 27.8-23.4 cal kyr BP), abrupt decline of T. sieboldii and some of deciduous broad-leaved taxa excluding Q. subgenus Quercus and occurrence of evergreen broad-leaved taxa (KD-II: ca. 10.1-10.0 cal kyr BP), and gradual decline of Q. subgenus Quercus and expansion of evergreen broad-leaved taxa along with Celtis and/or Aphananthe aspera (KD-III: ca. 9.5-8.4 cal kyr BP). Chronologically, zone KD-I correlates with the full-glacial period which is regarded as the cooling phase: 'Heinrich event 2' (between the Dansgaard - Oeschger cycles 3 and 2). Pollen records from Koda Mire and the adjacent area during this period indicate that mixed forest areas, comprising of temperate conifers and deciduous broad-leaved trees, were widely distributed across the Kochi Plain. Futhermore, the records suggest that it may not have served as refugia for Cryptomeria japonica and evergreen broad-leaved trees.

Premise of the study: We investigate factors supporting the persistence in southern China of a rare Tertiary relict tree species, Liriodendron chinense, which has been almost eliminated by recent land use conversion. We hypothesize that cultural practices and traditional sustainable forest resource uses provide niches for the species' regeneration that will complement infrequent natural disturbances, while the species' survival on remote mountain slopes where there are no humans depends on natural disturbances alone. Methods: We examined and analyzed various landscape contexts, community associations, age distributions, and regeneration patterns of Liriodendron chinense. Key results: Forest communities containing Liriodendron chinense were of three types: (1) village fengshui forests-mature forests dominated by Tertiary relict taxa Liriodendron, Toona, and Emmenopterys, protected for their supposed spiritual value; (2) young secondary forests near villages, dominated solely by Liriodendron; and (3) old secondary forest remnants on mountain slopes far from villages, dominated by Liriodendron with other Tertiary relicts of the genera Davidia and Sassafras. The age structure of Liriodendron indicated ample recruitment in the first two forest types, where the activities of local people have provided regeneration niches for the survival of this shade-intolerant pioneer species. On the remote mountain slopes that have never been converted to agriculture, Liriodendron has survived through regeneration made possible by natural disturbances. Conclusions: The traditional human land use, infl uenced by cultural values, has supplemented infrequent natural disturbances, providing regeneration niches for this and other Tertiary remnant species near villages in mountain valleys, while on uninhabited mountain slopes the species depends on natural disturbances to survive.

We conducted a transect survey on the leeward northern side and upwind southern side of a forest isolated in subalpine semi-natural grassland in Kirigamine, central Nagano Prefecture, to clarify the influence of a southwest wind on the invasion of trees into the grassland. Although Rhododendron japonicum and Malus toringo were scattered widely in the grassland, the other trees were likely to have been propagated from seed sources in theisolated forest. Poorer establishment of trees and lower tree heights in the grassland on the southern side indicates dryer soil on the southern side than on the northern side of the forest caused by the prevailing southwest wind. The composition of trees in the grassland on the leeward northern side of the forest was dominated to a greater extent by trees with wind-dispersed seeds than that on the upwind southern side, indicating that southwest winds havepromoted the dispersal of tree seeds to the northern side of the forest.

Premise of the study: The possible persistence of wild Ginkgo biloba populations in China has long been debated but never scientifically confirmed. We test our hypothesis that the extant Ginkgo populations in the Dalou Mountains (SW China) represent fragments of the original natural Ginkgo range and offer a range of pertinent perspectives on the living fossil Ginkgo's history, prehistory, ecology, and place in human culture-all important aspects of this highly valued species. Methods: We analyzed the vegetation of the study area, determined the population age structure of Ginkgo, and compared it to existing fossil records. For supporting material, we also examined records of the lack of human presence before the mid-17th century in the area, the local people's beliefs regarding preservation of the forests and existing genetic studies. Key results: Current species composition of Ginkgo forests in the Dalou Mountains agrees closely with floristic assemblages from fossil records bearing G. biloba. Current populations are found in habitats similar to those of fossil Ginkgo, which, as today, favored rock crevices. Female to male ratios are 3:2. Estimated ages for many of the trees show that Ginkgo was present in this area prior to human settlement and indigenous peoples of this area are unlikely to have planted Ginkgo because of traditional beliefs. Our results agree with existing genetic studies that show that these mountains were glacial refugia for G. biloba. Conclusions: The corroborative evidence confirms the finding that these populations represent fragments of the original natural Ginkgo in the valley and lower mountain slopes of the Dalou Mountains.

Archaeobotanical analysis of moat sediments from the Neolithic site of Chengtoushan, Hunan, China, provides evidence of the land-use change for rice and foxtail millet cultivation around the site. Rice constantly appeared through the three phases of Daxi culture with high percentages, while accompanying wetland species of paddy field weeds gradually decreased. In contrast, foxtail millet increased together with upland field and ruderal weeds through the time. These changes suggest that foxtail millet cultivation was established with the expansion of dry farming in region of the site, while rice cultivation was continuously practiced on the alluvial plain surrounding the site. This diversification of land-use through the addition of foxtail millet cultivation may be attributed to population increase or as a buffer to natural disasters such as flooding. In addition, gathering of wild nuts and fruits continued alongside cultivation. These multiple strategies for food procurement provided sustainable food supply for the population of Chengtoushan for 1,800 years.

日光金精山亜高山針葉樹林林床にみられる蘚苔類の生育地特性を明らかにするために,生育地の土壌水分率を測定し,種間の比較を行った。調査地のわずか20mのライン上に最低の9%から最高の84%までという大きな土壌分の違いがみられた。ホソバミズゴケ(Sphagnum girgensohnii)の生育地の土壌水分率が最も高く,コケが生育していない場所でも土壌水分率は比較的高く,オオシノブゴケ(Thuidium tamariscinum)の生育地の土壌水分率は最も低かった。明らかにされた蘚苔類の分布と土壌水分率の関係から,水分状態が異なる土壌に蘚苔類が選択的に生育していると考えられた。

1. ミツデウラボシの生育立地である乾燥した崖地は,胞子が雨水によって斜面下部へ流出しやすいだけでなく,前葉体が乾燥にさらされてしまうため定着しにくいと予想された.<BR>2. ミツデウラボシの生育立地に群落を形成していた蘇苔類に着目して,蘇苔類の被度とミツデウラボシの幼胞子体の分布を比較した.<BR>3. ミツデウラボシの幼胞子体は,蘇苔類群落が多く生育する小方形区ほど分布している割合が高かった.<BR>4. 蘇苔類群落内は露出した地表面に比べ,散布された胞子が雨水によって流出しにくいため,定着しやすいと考えられた.<BR> 5. 蘇苔類群落内は湿潤環境が維持され,胞子の発芽や前葉体での受精が容易になるため,幼胞子体の分布密度が高くなると考えられた.

本研究では，千葉大学松戸キャンパス内のコケフロラを記載し，それらの生態分布を明らかにすることを目的とした．キャンパス内では，ツノゴケ類は確認されず，蘚類11科18属23種，苔類6科7属9種の計17科25属32種のコケ植物が確認された．この割合は，千葉市の農村地区でのコケ植物の出現割合と近い値だった．キャンパス内でも確認されたコケ植物のすべてが都市環境で普通に見られる種であり，人為的影響に弱い種は確認されなかった．これは，松戸キャンパスの樹林地は都市の孤立林であり，環境変化の影響を受けやすいことが原因だと思われる．松戸キャンパスには農地や庭園など多様な環境があるため，大気汚染が緩和されており，コケ植物が多く確認されたと考えられる．

Fern flora in the Matsudo campus has not been studied since 1933. To clarify existing species diversity of fernwhich is susceptible to urbanization and disturbance by planting, we made up a fern flora of the Matsudo Campus,Faculty of Horticulture, Chiba University. We found 34 taxa of ferns including 12 family, 17 genus, 31 species, 1subspecies, 1 variety, and 1 hybrid species. Thirty species including aquatic ferns such as Azolla imbricata,Salvinia natans, and Marsilea quadrifolia have disappeared from the Matsudo Campus. Extinction of the aquaticferns was possibly caused to reclamation of paddy fields. We added species that were not found in 1933, includingDryopteris sacrosancta and Polystichum × ohtanii that are rare in Chiba Prefecture. It is necessary formaintenance of the species diversity to prevent habitats of ferns from aridification that is mainly attributed tofelling and trimming of trees.

瀬戸内海中部・出崎海岸（岡山県玉野市）の埋没泥炭層について，その堆積環境を再検討し，完新世の相対的海水準変動との関係を考察した．泥炭層は，完新世中期のおもに約7,000～6,600 cal BPの間に，塩性湿地で形成された．この時期は，瀬戸内海沿岸域における完新世の相対的高海水準期に相当し，泥炭層は約7,000 cal BPに海水準上昇が鈍化する一方で，当該地域に及んだ海進に伴って形成されはじめた．泥炭層は高潮位面と最高潮位面との間で形成されたと考えられ，当時の潮位差が現在と同程度であったとすれば，泥炭層形成期間中の約400年間に相対的海水準は0.27～1.27 m以上（妥当な最大値は0.5～0.7 m）上昇し，約6,700～6,600 cal BPに最高位まで達したと推定される．調査地域における局地的な沈降量を考慮しても，この間の海水準上昇はユースタティックな要因によると考えられる．