土耳其安纳托利亚中部乔鲁姆-阿马西亚地区始新世孢粉的地层和古环境意义

主要研究安纳托利亚中部昌克勒－乔鲁姆盆地（Cankiri-Corum Basin)始新世含褐煤层中的孢粉与环境,在采尔特克组（Celtek Fm.)30块洋品共发现至少100种孢粉型,包括部分具地层意义的分子,从而确定孢粉组合的时代为中－？晚始新世,孢粉反映本组褐煤层形成于近湖沼泽环境或具有茂密低地植被的泛滥平原,在乔鲁姆－阿马西亚地区的阿姆特鲁组（Armutlu Fm.)中共发现59属,133种孢粉,包括部分现代分布在大西洋和印度－太平洋地区的曲线红树林分子,为土耳其红树林化石花粉的首次记录,说明沉积时期受到海陆的共同作用,可能为潮间带沼泽环境,奥斯曼诺格鲁组（Osmanoqlu Fm.)的褐煤层中也含有丰富的孢粉,指示地层时代为早渐新世。     

Palynology and palynofacies of Miocene coal-bearing (clastic) sediments of the Hausruck area (Austria)

Two drill cores with coal-bearing sediments from the localities Lukasberg and Kalletsberg of the Hausruck area were investigated. Particular attention was paid to the clastic intercalations between and within the coal seams to complete the previous database of the coal-petrological and geochemical analyses of the coals made by Gruber and Sachsenhofer (1999) and Bechtel et al. (2003). In this work, pollen and spores, the acid-resistant organic components (palynofacies), and the total organic carbon content (TOC) of the clastic sediments have been examined in order to interpret the palaecological conditions of the different plant habitats. The TOC and structured components of the Lukasberg site displayed a recurring cyclicity between coal seams and are interpreted as frequent changes of the depositional environment: coal swamps and peat bogs, lacustrine conditions (lake or pond) and marshes or clastic swamps. It is therefore assumed that the Hausruck area, particularly at the Lukasberg locality, was subjected to periodical submersions, in which the ground-water level repeatedly flooded the coal swamps. This cyclicity is unfortunately not clearly documented at the Kalletsberg locality. In addition, the occurrence of up to 32% fusinite in the palynofacies from some samples of both sites and charred logs at the Lukasberg open cast mine indicate the presence of palaeo-wildfires within forests of the Hausruck area. The age of the sedimentary succession is late Sarmatian to the early/middle Pannonian (upper Middle Miocene to lower Upper Miocene). The frequent occurrences of pollen of Mastixia, a warmth loving plant, which during this time interval occurred sporadically and in low numbers, suggest that the Hausruck was a relict area with a particular humid and warm climate.     

Stratigraphy and palynology of the Pennsylvanian continental Buçaco Basin (NW Iberia)

The Buçaco Basin is a Pennsylvanian continental basin located along an important NNW–SSE strike structure (Porto-Tomar-Ferreira do Alentejo shear zone) that separates the Ossa-Morena and Central Iberian Zones of the Iberian Variscan Fold Belt in central western Portugal. The shear zone controlled the sedimentation in the basin and probably its post-sedimentary evolution. Sedimentation is initially alluvial with characteristic red sandstones, breccias and conglomerates. A gradual change to a fluvial (and probably lacustrine) type of sedimentation is observed with finning-upward cycles of gravel conglomerates, sandstones and organic-rich mudstones with occasional coal seams. Three representative sections were sampled for palynology and seventeen samples yielded sporomorphs with moderate to poor preservation. The palynological content from the alluvial sediments shows low diversity and poorly preserved assemblages dominated by Triquitrites spp., Densosporites spp., Laevigatosporites spp., and other taxa associated with siliciclastic environments or rheophytic mires. The fluvial and lacustrine sediments show a dramatic increase in diversity with an abundant, typical peatland microflora including sporomorphs such as Endosporites spp., Lycospora spp. and Monoletes spp., but also marginal peat and siliciclastic substrate taxa such as Densosporites spp., Latensina/Cordaitina spp., and Florinites spp. Other common taxa are Cheiledonites spp., Crassispora spp., Dictyotriletes-like miospores (mostly fragments), Potonieisporites spp., and Wilsonites spp. The presence and considerable abundance of Potonieisporites novicus and Cheiledonites cf. major is indicative of the middle to upper Potonieisporites novicus-bhardwajii–Cheiledonites major (NBM) miospore biozone of Western Europe, corresponding to the late Stephanian (early Gzhelian).     

Some mire systems in Japan

Summary

Some examples of different types of mires in Japan are described and compared with their European counterparts. The parallels in ecosystem development and vegetation physiognomy with mires in equivalent habitats in Europe are striking. Numerous species are common to both, in other cases closely related species fill similar niches. In some instances, however, a given species displays marked ecological differences in the two regions.

The flood plain mires of Hokkaido and the mires of Oze and Kirigamine are among the finest examples of their kind in the world. Those in the mountain districts are adequately protected in National Parks: it is suggested that the lowland mires of Hokkaido require further protection.     

Stratigraphic occurrences and vegetational patterns of Pennsylvanian pteridosperms in Euramerican coal swamps

The vegetation of many Euramerican coal swamps is known from coal-ball peats in the tropical rainy zone across the paleocontinent of Laurussia in the Upper Carboniferous. The stratigraphic occurrences of coal balls in Europe (lower Westphalian) and in North America (upper Westphalian and lower Stephanian) are largely complementary and a revised correlation chart is given. Quantitative analyses of the vegetation from these autochthonous peats are combined with coal palynology to determine on overview of swamp vegetation patterns during the Westphalian and early Stephanian. In comparison to the dominance and great diversity of pteridosperms in the Upper Carboniferous compression floras, seed ferns were minor to subdominant elements in the coal-ball peats. The quantitative composition of organ assemblages of the principal pteridosperms is given with stratigraphic occurrences of Medullosa and Sutcliffia (Medullosaceae), Heterangium, Lyginopteris, Microspermopteris, and Schopfiastrum (Lyginopteridaceaea) and Callistophyton (Callistophytaceae). The major peat contributors among pteridosperms are Lyginopteris (?90%) in the Westphalian A and Medullosa (?95%) in the Westphalian D and Stephanian. Lyginopteris became extinct in the early Westphalian B and Medullosa became abundant during the Westphalian C–D transition and a subdominant in the Stephanian contributing 13–21% of the permineralized peats. Paleoecological interpretations indicate that medullosan trees were most abundant but patchy in distribution in drier swamp stages with enriched nutrients and near major channels in swamps during the Westphalian D. It is suggested that the swamp pteridosperms are probably quite similar to or identical with some of the representatives in the more diverse compression floras. The evolution and diversity noted in swamp pteridosperms are considered principally the product of adjacent lowland communities which repeatedly introduced seeds into the wetlands. The swamp pteridosperms exhibit the greatest fluctuation in abundance (biomass) from site to site in the same coal, probably the highest level of diversity and the only steady pattern of increase in importance during the Late Carboniferous with the possible exception of the Westphalian B–C interval. The close relationships inferred between swamp pteridosperms and their lowland seed sources are also compatible with the frequent association of tree ferns and seed ferns during the Westphalian D and in the Stephanian when these two kinds of frond-bearing trees formed most of the vegetation in both lowland and swamp environments.     

Palynofacies and spore assemblage variations of upper Viséan (Mississippian) strata across the southern North Sea

Viséan strata are penetrated by exploration wells in the southern North Sea, reaching from the Firth of Forth in Scotland to offshore northwest Germany and to Rügen Island, northeastern Germany, south of the Baltic Sea. Several wells have been studied representing different late Viséan depositional settings ranging from proximal near-shore clastic facies (Firth of Forth, Northwest of Germany) to distal carbonate platform facies (Rügen Island). Variations of the miospore assemblages from the coeval (NM and VF Miospore Biozones) parts of these sections were analyzed with respect to palynofacies, spore abundance; morphological composition; diversity and palaeobotanical/palaeoecological affinities. While assemblages from similar down-depositional dip facies settings remain similar (even over east-west distances of > 750 km), all of the above attributes show significant variations from proximal to distal depositional settings (< 200 km to the southeast). These down-depositional dip changes appear to be continuous, but the greatest degree of change is seen at the boundaries between deltaic and non-deltaic near shore facies; between near-shore coastal clastic and carbonate platform facies; and between inner-and outer-carbonate platform facies.Miospore abundances, assemblage diversities and the number of coincident genera between the sections are reduced in moving towards distal depositional settings. This reduction most effects rounded triangular and triangular miospores, while the proportion of rounded miospores increases significantly. The palaeobotanical/palaeoecological character of the miospores also clearly changes in moving from coastal clastic to carbonate platform depositional settings. These changes appear to be largely controlled by taphonomic effects such as primary input and sorting during transportation and deposition, such that a facies-related pattern is apparent. Variations in late Viséan miospore assemblages across the studied area appear to be most closely related to the different facies realms suggesting that previously identified differences in miospore assemblages from Germany and Britain reflect depositional facies rather than regional variations in parent vegetation or climate.     

Holocene space-time succession of the Middle Atrato wetlands, Chocó biogeographic region, Colombia

Successional sequences from forested wetlands in the Middle Atrato River Basin were reconstructed using characterisation of present vegetation communities and palynological analysis. A 4.8 km transect, drawn across a river meander, and two 6 and 8 m deep sediment cores (San Martín and Villanueva) were collected in the floodplain within two different vegetation assemblages. Based on the floristic and environmental characteristics of the local vegetation communities, ecological changes spanning the last 4 ka (cal years BP) were analysed in San Martín and Villanueva cores. Present vegetation is dominated by four communities determined by flood tolerance and drainage conditions. We found Euterpe oleraceae, Mauritiella macroclada-Campnosperma panamensis and Oenocarpus bataua forests, and mixed forest and open vegetation in a gradient from poor to improved drainage conditions. Vegetation changes in the palynological record suggest that sedimentation and erosion processes on flood basins are due to changes in drainage conditions and to variable flooding levels.A wet period in the 4 to 2.7 ka interval is postulated, which might be related to sea level rise or local subsidence. Lower flooding levels and improved drainage conditions dominated the 2.7 to ∼ 1.6 ka interval, whereas a flooding event (and a hiatus) occurred between 1.5 and 0.5 ka. This flooding event might be synchronous with analogous events as recorded in the Colombian Amazonia between 1.6 and 1.45 ka. Forest disturbance, probably of anthropogenic origin, is recorded in both sites since 0.5 ka.     

LYCOSPORA FROM CARBONIFEROUS LEPIDOSTROBUS COMPRESSIONS

Spores were extracted from Carboniferous Lepidostrobus compressions in order to associate in situ microspores with dispersed species of Lycospora. Two hundred twenty-six cones were examined, of which 61 contained spores. Fertile cones came from the Westphalian D of England, Namurian B through Westphalian D of the Appalachian and Illinois basins, and the Westphalian D of the Western Interior. Cones were separated into species based on microspore and cone morphology. Lycospora trigonoreticulata was produced by Lepidostrobus princeps from Westphalian C-D rocks from Missouri, the Illinois Basin, and the Appalachian Basin. Lycospora rotunda was produced by Lepidostrobus sp. A from Westphalian A rocks of Alabama. Two cone species produced Lycospora torquifer: Lepidostrobus praelongus from the Westphalian D of Pennsylvania and Lepidostrobus variabilis from the Westphalian A and C of the Illinois and Appalachian basins. Lycospora punctata was produced by Lepidostrobus cf. squarrosus from the Westphalian D of England, the Appalachian Basin, and Illinois Basin. Lycospora noctuina was produced by Lepidostrobus haslingdenensis from the Namurian B/C of Illinois. Microspore species are differentiated primarily on the basis of size, cingulum structure and width, and ornamentation. Cone species differ in width and distal lamina size, shape, and attitude. Lycospora species isolated from clastic species of Lepidostrobus differ completely from those of coal-swamp species, confirming that lycopod trees from clastic environments represent biologically different species from those centered in coal swamps.     

Flora and dispersed cuticles from the coal seams in the Jan pit of the Šverma coal mine in Žacléř (Bashkirian,Intrasudetic Basin,Czech Republic)

The Lampertice Member in the ?aclé? coalfield represents the long-term coal-bearing deposition of nearly all Upper Bashkitian (Namurian to Ducmantian). Nearly the whole thickness, more than 600 m was revealed during the construction of the Jan pit of the Jan ?verma coal mine during 1958–1962. Z. Rieger collected stratigraphically determined plant remains for later evaluation and he also sampled individual coal seams. The plant material was evaluated again and four coal samples were macerated for cuticles to expand our knowledge of ?aclé? flora. The following local biozones are valid for the Lampertice Member. The Namutian (Yeadonian) Mariopteris glabra Zone lasts from the basal coal-barren rocks till lower coal seam 17 (there are 24 lower coal seams). The Langsettian is crowed by the LAD of Neuralethopteris schlehanii (Stur) Laveine at upper coal seam 20 (there are 32 upper coal seams). The Langsettian can be divided into the upper and lower parts by FAD of Lonchopteris Brongniart at about lower coal seam 8. The Upper Duckmantian is defined by the FAD of Linopteris neuropteroides Gutbier forma major Potonié from about upper coal seam 11 upwards. The results of cuticular analysis are as follows: Undeterminable cuticles with polygonal or tetragonal, randomly or parallel oriented cells dominate. Such cuticles predominantly belong to seeds. Cordaitalean cuticles are common in three of four samples. They are assigned to the genera Cordaites Unger, Cordaadaxicutis ?im?nek et Florjan, and Cordaabaxicutis ?im?nek et Florjan. Pteridosperm cuticles are very rare—Silesiacutis prosenchymatica Roselt et Schneider and undetermined cuticles with probably neuropterid cyclopterid affinity.     

Leaching from vegetation of soluble polyphenolic compounds,and their abundance in temporary ponds in the Doñana National Park (SW Spain)

The origin of allochthonous soluble polyphenols in the water of the temporary ponds of Doñana National Park during flood and heavy rainfall was examined. Soil and litter samples were found to leach large quantities of polyphenolic compounds. The concentration of these compounds showed a significant correlation with the organic content of the soil samples, but indicated no correlation with the litter samples. Rain simulation tests proved that fresh vegetation leached soluble polyphenolic compounds. Mediterranean scrub (Cystaceae) from dry poor-nutrient soils yielded the highest concentration (being furthest away from the ponds), whereas wetland (Ericaceae) and littoral vegetation (Juncaceae and Cyperaceae) rated second and third, respectively. The potential of the surrounding vegetation to leach high concentrations of polyphenolic compounds suggests that this is the main source of the rapid polyphenolic enrichment of these ponds during periods of heavy rain.     

The Crassispora kosankei–Cystoptychus azcuyi palynozone of the Upper Carboniferous Tupambi Formation,Tarija Basin,northern Argentina

Well-preserved and diverse palynomorph assemblages were recovered from surface and core samples from the middle to upper section of the Tupambi Formation. The latter is the basal unit of the Macharetı́ Group (Upper Carboniferous) of the Tarija Basin, northern Argentina. Assemblages are composed of trilete miospores, one hilate species, monosaccate pollen grains (one species striated), one praecolpate species and green algae (Botryococcus). Two key species are Cystoptychus azcuyi sp. nov. and Crassispora kosankei (Potonié and Kremp) Bharadwaj emend. Smith and Butterworth enable definition of the first palynozone for this basin. The age, as well as the biostratigraphic and paleogeographic significance of the palynoflora is discussed.     

Botanical diversity in British mires

Although mires are sometimes regarded as a single, specific and even esoteric habitat-type, in their full range of development-calcareous fens to acidic bogs, lowland swamps to upland flushes, woodlands, sedgelands and mosslands-they occupy a wide range of environmental conditions and sustain a rich botanical resource. Here an outline is given of the types of mires that are widespread in Britain and their botanical resource. It is discussed with reference to some of the environmental variables and management conditions that have been shown to influence the species composition and diversity of their vegetation. Some implications that this has for the classification of mires are outlined.     

Synchronous Wildfire Activity Rise and Mire Deforestation at the Triassic–Jurassic Boundary

The end-Triassic mass extinction event (∼201.4 million years ago) caused major faunal and floral turnovers in both the marine and terrestrial realms. The biotic changes have been attributed to extreme greenhouse warming across the Triassic–Jurassic (T–J) boundary caused by massive release of carbon dioxide and/or methane related to extensive volcanism in the Central Atlantic Magmatic Province (CAMP), resulting in a more humid climate with increased storminess and lightning activity. Lightning strikes are considered the primary source of wildfires, producing charcoal, microscopically recognized as inertinite macerals. The presence of polycyclic aromatic hydrocarbons (PAHs) of pyrolytic origin and allochthonous charcoal in siliciclastic T–J boundary strata has suggested widespread wildfire activity at the time. We have investigated largely autochthonous coal and coaly beds across the T–J boundary in Sweden and Denmark. These beds consist of predominantly organic material from the in situ vegetation in the mires, and as the coaly beds represent a substantial period of time they are excellent environmental archives. We document a remarkable increase in inertinite content in the coal and coaly beds across the T–J boundary. We show estimated burning temperatures derived from inertinite reflectance measurements coupled with palynological data and conclude that pre-boundary late Rhaetian mire wildfires included high-temperature crown fires, whereas latest Rhaetian–Sinemurian mire wildfires were more frequent but dominated by lower temperature surface fires. Our results suggest a major change in the mire ecosystems across the T–J boundary from forested, conifer dominated mires to mires with a predominantly herbaceous and shrubby vegetation. Contrary to the overall regional vegetation for which onset of recovery commenced in the early Hettangian, the sensitive mire ecosystem remained affected during the Hettangian and did not start to recover until around the Hettangian–Sinemurian boundary. Decreasing inertinite content through the Lower Jurassic suggests that fire activity gradually resumed to considerable lower levels.     

Albian Palynostratigraphy of ODP Leg 207 (Holes 1257A, 1258C and 1260B), Demerara Rise,Equatorial Atlantic

Palynological analyses were carried out in 96 core samples with the objective of determining the relative age of calcareous clays, in holes 1257A, 1258C and 1260B of ODP Leg 207, drilled on the Demerara Rise, northern coast of Suriname, Equatorial Atlantic. The palynological assemblages recovered consisted of spores, pollen grains, dinoflagellate cysts, palynoforaminifers and prasinophytes and appeared reasonably well preserved. The miospores showed little diversification, where the most significant genera were Crybelosporites and Elaterosporites. The dinocysts showed greater diversity and abundance, predominating over the miospores in the three holes. In the three holes analyzed, eight genera and three species of spores, eight genera and eleven species of pollen grains, and 24 genera and 44 species of dinoflagellates were identified. The middle to late Albian age was determined on the basis of bioevents of recognized species with chronostratigraphic value. The species diagnosed mostly included the miospores Elaterosporites protensus, Elaterosporites verrucatus, Inaperturopollenites simplex and the dinocysts Cribroperidinium muderongense, Dinopterygium cladoides, Litosphaeridium arundum, Litosphaeridium conispinum, Oligosphaeridium complex and Stiphrosphaeridium anthophorum.     

Siluro-Devonian miospore biostratigraphy of the Urubu River area, western Amazon Basin, northern Brazil

Well-preserved miospores have been observed in the Urubu River area from the western part of the Amazon Basin, northern Brazil, in rocks belonging to the uppermost Pitinga and Manacapuru Formations. A previous palynological work based on chitinozoans has dated these strata as Late Ludlow, Early Pridoli and Early Lochkovian. Although samples are relatively poor in miospores, the present study reveals the most diversified Silurian-Earliest Lochkovian palynoflora ever reported from South America, an interval where miospore information is still very rare. Sixty-four species have been identified, of which two are new (Artemopyra urubuense and Retusotriletes amazonensis). One single specimen attributed to the genus Grandispora, identical to unpublished forms identified by one of us (P.S.) in Lochkovian sections of Saudi Arabia, has been found in a Lochkovian sample from the Urubu River. These constitute the oldest geological record of Grandispora. Among the abundant acritarchs, specimens of the genus Schizocystia have been observed for the first time in pre-Devonian rocks.Although the Late Silurian-Early Lochkovian miospore biostratigraphy is still in its infancy in South America, it seems that Amazon Basin assemblages do not show significant differences in composition in comparison to coeval palynofloras from other areas of northwestern Gondwana. This is surprising since the miospore localities under consideration are widely distributed over high to low paleolatitudes, i.e. from cool temperate to dry subtropical belts. Conversely, Siluro-Devonian Gondwanan assemblages differ considerably from the contemporary palynofloras of the Old Red Sandstone Continent and adjacent areas, thus contradicting recent phytogeographic interpretations based on megafloras.     

Abgebrannte flachmoorhorizonte im kulturschichtprofil schweizerischer seeufersiedlungen?

Zusammenfassung Pflanzliche Makrofossilien in der neolithischen Kulturschicht Seeberg-Brugäschisee-Süd werden als Reste eines abgebrannten Flachmoorhorizontes angesprochen. Ferner werden Beobachtungen an rezenten und postglazialen Carex lasiocarpa-Gesellschaften mitgeteilt.

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Summary The study of macroscopic plant remains (fruits and seeds) from the neolithic settlement Burgäschisee South (Villaret-Von Rochow, 1967) raised the question whether the origin of the rootlet peat (Radizellentorf) in the lower level of the archeological layer is partly due to a sedge fen vegetation with Carex lasiocarpa and Equisetum palustre as dominants. Vogt's definition of the archeological layer (Kulturschicht) stresses its complex character; and we think that organic matter from types of swamp vegetation upon which a settlement was located may be found not underneath but within the archeological layer itself. But these organic matters may easily be destroyed by fire.In 1956 Dr. W. Lüdi and the author studied numerous peat cliffs located in different parts of Switzerland. From these studies it appears that the vegetation types of Carex lasiocarpa, in some localities associated with Scheuchzeria palustris peat, had been of rather widespread occurrence in Swiss mires during the boreal, atlantic and subboreal period. These mires sometimes developed into raised bog communities.The ecology and variation of pH of some of the few recent Carex lasiocarpa swamps is briefly discussed. Characteristic swellings of rootlets of Carex lasiocarpa containing hyphae seem to indicate mycorrhiza-like association with some fungus.

     

A phytosociological classification of Swiss mire vegetation

The mapping and monitoring of Swiss mires has so far relied on a classification system based on expert judgement, which was not supported by a quantitative vegetation analysis and which did not include all wetland vegetation types described in the country. Based on a spatially representative sample of 17,608 relevés from 112 Swiss mires, we address the following questions: (1) How abundant are wetland vegetation types (phytosociological alliances) in Swiss mires? (2) How are they distributed across the country––is there a regional pattern? (3) How clearly are they separated from each other? (4) How clear and reliable is their ecological interpretation? Using published wetland vegetation relevés and lists of diagnostic species for phytosociological units (associations and alliances) established by experts, we developed a numerical method for assigning relevés to units through the calculation of similarity indices. We applied this method to our sample of 17,608 relevés and estimated the total area covered by each vegetation type in Switzerland. We found that vegetation types not included in previous mapping were either rare in Switzerland (partly due to mire drainage) or poorly distinguished from other vegetation units. In an ordination, the Swiss mire vegetation formed a triangular gradient system with the Sphagnion medii, the Caricion davallianae and the Phragmition australis as extreme types. Phytosociological alliances were clearly separated in a subset of 2,265 relevés, which had a strong similarity to one particular association, but poorly separated across all relevés, of which many could not be unequivocally assigned to one association. However, ecological gradients were reflected equally well by the vegetation types in either case. Overall, phytosociological alliances distinguished until now proved suitable schemes to describe and interpret vegetation gradients. Nevertheless, we see the urgent need to establish a data base of Swiss wetland relevés for a more reliable definition of some vegetation units.     

Cordaites schatzlarensis sp. nov. and Samaropsis newberryi (Andrews) Seward from the Westphalian (Carboniferous) of the ?aclé? area (Czech Republic)

The monotonous cordaitalean leaves are usually difficult to determine as leaf shape and venation can be similar in many species. Therefore cuticular analysis is an important method for distinguishing cordaitalean leaves. Pennsylvanian Cordaites schatzlarensis nov. sp. comes from the ?aclé? locality in the Intrasudetic Basin, Czech Republic. It has been found in mudstone accompanying the upper coal seams No. 9 and 10 of the Jan Šverma Coals, Lampertice Member, ?aclé? Formation and are late Duckmantian in age. The leaves of Cordaites schatzlarensis are lanceolate, amphistomatic. Stomata of the adaxial epidermis are scarce, isolated, or in very short stomatal rows. In contrast, the density of stomata on the abaxial cuticle is high and stomata are arranged into single or double stomatal rows. The cuticles of C. schatzlarensis are comparable with the Chinese Upper Permian C. baodeensis Ge. Leaves can be narrow, comparable to French Bolsovian Dorycordaites zeilleri Ledran, or relatively wide. Accompanying big seeds more than 5 cm in diameter are attributed to Samaropsis newberryi (Andrews) Seward. The pith casts Artisia Sternberg were found in sandy channel fill deposits.     

Diatom communities along pH and hydrological gradients in three montane mires,central China

The distribution patterns of epiphytic diatom assemblages in three montane mires in central China were investigated to examine their relationships with selected environmental variables (pH and depth to water table, DWT). Two of the mires are considered to be in good ecological condition (Dajiuhu and Qizimeishan Mires) while Erxianyan Mire is extensively affected by acid deposition and human activities. A total of 206 taxa belonging to 56 genera were found in 44 Sphagnum samples. Multivariate analysis revealed that pH and DWT were significantly correlated with diatom distribution. In Erxianyan Mire, the characteristic taxa (Eunotia minor and Eunotia intermedia) had lower pH optima and may therefore be useful indicators of highly-acidic conditions. In Dajiuhu Mire, the dominant species had higher pH optima, and abundant xerotolerant taxa (Hantzschia amphioxys, Pinnularia borealis, Luticola mutica and Diadesmis contenta) were observed. In the partial canonical correspondence analyses with mire location as a covariable, the correlation between diatom data and pH was insignificant, likely because pH differences between mires were greater than those within mires. In contrast, diatom data were significantly correlated with DWT, suggesting that diatoms are good sensors of hydrological variability along the hollow to hummock gradient. Together, these data can expand current autecological information for these potential diatom indicator species, which is critical for refining our interpretations of bio-monitoring and palaeolimnological studies in montane mires.