Basis Of Palynology Research Articles

SEM Study of Leaf Epidermis and Spores of Nine Species Of Dryopteris Adans. From Shandong Province, China

Scanning Electron Microscopy (SEM) structures of leaf epidermis and spores of 9 species of Dryopteris Adans. from Shandong Province of China were studied. These species are: Dryopteris erythrosora (Eaton) O. Ktze., D. fuscipes C. Chr., D. tsoongii Ching, D. crassirhizoma Nakai and D. championii (Benth.) C. Chr., D. lijianxiuii X. J. Li (new species), D. shandongensis J. X. Li & F. Li, D. laoshanensis J. X. Li & S. T. Ma and D. parachinensis Ching & F. Z. Li. The study showed that the perispore ornamentation and submicroscopic structural characteristics of peripheral wall of leaf epidermal cells were stable within each species and have significant differences between species. It does not only provide evidences of submicroscopic structural characteristics for its morphological classification, but also provides a palynological basis for the classification and identification of new pteridophyte resources of Shandong area. A new Identification Key to 9 species of Dryopteris Adans. is prepared using both morphological and SEM characters of spores and leaf epidermis. Therefore, the submicroscopic structural characteristics of palynology and the leaf epidermis of the genus were of great significance in taxonomy. Bangladesh J. Bot. 51(4): 951-960, 2022 (December) Special

Palynology of Polypodiaceae from Shandong and its significance in classification

According to the new classification system of international Lycopods and Ferns in the Flora of China,Polypodiaceae includes more than 20 genus of Polypodiaceae in the Qinrenchang classification system,and also includes independent families such as Drynariaceae and Platyceriaceae.The new classification system of Polypodiaceae in the Flora of China with many issues needs further investigation and classification.Here we investigated the spore morphology and perispore ornamentation submicroscopic structure of Polypodiaceae from Shandong Province using scanning electron microscopy(SEM).This is the first palynological study based on the new classification system of Polypodiaceae.The results were as follows: Spores of Polypodiaceae were reniform,bilaterally symmetrical,possessing a perispore with stable ornamentation within species and clear distinctions between subfamily,genus and species.The palynological studies supported two of the subfamilies of Polypodiaceae-Drynaria and Platycerium delineated in the FOC.In addition,the perispore ornamentation combined with leaf morphological characteristics showed that Phymatopteris shandongensis J.X.Li et C.Y.Wang was a distinct species,and should be restored to a species level position rather than incorporated with P.hastata(Thunb.) Pic.Serm.,not regard as Phymatopteris but as a new combination Selliguea shandongensis(J.X.Li et C.Y.Wang) J.X.Li & X.J.Li,comb.nov.according to the International Code of Botanical Nomenclature and the classification system of Flora of China.Our study not only has accumulated new information for the palynology of Polypodiaceae,but also provides a palynological basis for its new classification system,which is consistent with molecular analysis,and confirms the rationality of the new classification system of Polypodiaceae and its subfamilies.

Palynology of Cenozoic successions of Kerala Basin: a review from the perspective of biostratigraphy and palaeoclimatic studies

The Kerala Basin is only onshore opportunity to study Cenozoic palaeoclimate and palaeoenvironment of southwest India encompassing Neogene global events such as Mid Miocene Climate Optimum (MMCO) and even older times of Palaeogene. The global warming during ~17–15 Ma (MMCO), enhanced annual surface temperature 3–4° C higher than the present, is equivalent to the warming predicted for the next century. Since the palaeogeographical and other general conditions have not been much changed from the Miocene Period, Neogene palaeoclimate of Kerala Basin can be considered as a possible analogue for future climate. Many workers have studied the Cenozoic sedimentary successions of surface and subsurface for stratigraphic classification of the rocks, but still, discrepancy persists in the chronostratigraphic relationship in sedimentary successions. The palynological investigations have also been limited mainly to palynofloral and palaeoecological inferences except a few in which palynostratigraphy, correlation and age have been attempted on the basis of spore–pollen only. Major three Cenozones namely, Triangulorites bellus and Crassoretitriletes vanraadshooveni (Eocene–Oligocene) and Malvacearumpollis bakonyensis (Miocene) have been established. The palynological studies done in the region broadly suggest warm and humid climate with heavy rainfall. However, the recent quantitative studies have highlighted the complexity of palaeoclimatic evolution in the tropics in terms of monsoon. A time–constrained quantitative palaeovegetation and palaeoclimate reconstructions on the basis of palynology is required for evaluation of response and changes in the tropical flora of northwestern India across the major climate events. For that, the biostratigraphy of finer resolution based on systematic and integrated multi–biotic proxy is needed to establish an age model for these sedimentary successions.

Pollen morphology of selected species from the family Solanaceae

ABSTRACTThe pollen grains of 38 species and one variety of 17 genera in the family Solanaceae were studied using light microscopy (LM) and scanning electron microscopy (SEM). Among them, the pollen morphology of 13 species was described for the first time. Our results suggested that the exine ornamentation of pollen grains could be divided into 11 types, made up of three types (cerebroid, granulate-perforate-punctate and rugulate-perforate) which were observed for the first time in Solanaceae, and other normal types (granulate, granulate-perforate, punctate, reticulate, rugulate, rugulate-striate, spinulose-perforate, striate). In addition, the studied species have pollen grains that differ in size, shape, equatorial view, polar view, aperture features and exine ornamentation, confirming that Solanaceae is a eurypalynous family. Furthermore, the intergeneric and intrageneric relationships of Solanaceae were explored. These results could provide a palynological basis for classification and systematic study of Solanaceae.

Pollen Morphology of Herbaceous Peonies with Different Ploidy Levels

The pollen morphology of 26 cultivars of herbaceous peony (Paeonia L.) was examined by scanning electron microscopy (SEM). Pollen grains of the cultivars were mostly subprolate to perprolate, tricolporate, or ellipsoidal in equatorial view, but rounded-trifid in polar view. The poles of pollen grains were mainly flat when viewed in cross-section and only a few appeared to have a circular or arc shape. In addition, the surface of the pollen grains was psilate, and the muri were partly or fully protuberant with a reticulate surface sculpture. However, the shapes and sizes of pollen grains as well as surface ornamentation varied significantly among cultivars with different chromosome numbers. The pollen grains from diploid cultivars were regular and full, and the reticulation holes were evenly distributed, while most of the pollen grains from triploid cultivars were empty flat shells with some heteromorphic pollen whose surface ornamentation was mostly rugulate-reticulate exine. The pollen grains from tetraploid cultivars were the largest although pollen morphology and surface ornamentation differed between Athena and Cream Delight. Six indices [polar axis length (P), equator axis length (E), P/E, pollen perforation diameter (D), ridge width (W), and D/W] were used in Q cluster analysis, which divided the 26 cultivars into three groups. Group I included eight diploid, four triploid, and one tetraploid cultivar. Group II included 12 triploid cultivars with complex genetic backgrounds. Group III included only one tetraploid cultivar Cream Delight. This work may provide an important palynological basis for studying taxonomy and hybrid breeding of herbaceous peony cultivars.

Palynological record of tropical rain forest vegetation and sea level fluctuations since 140 ka from sediment core, south-eastern Arabian Sea

Palyno-chronological study of a 552cm deep sediment core from the south-eastern Arabian Sea covers a time span of ~140ka. The age estimate is based on oxygen isotopic data of planktic foraminifera. Six zones were identified on the basis of palynology covering partially MIS-6 and MIS-5 to MIS-1 (Marine Isotopic Stages). The interglacial period (MIS-5) shows high rate of sedimentation corresponding to high percentage of terrestrial rain forest pollen. The palynological study reveals highstand and intense rain forest vegetation during MIS 5a which corresponds to the similar earlier records of estuarine ecosystem on land in Kerala. The relative sea level rise and fall since ~140ka have been inferred through quantitative estimate of marine versus terrestrial palynomorphs. The terrigenous non-pollen forms comprised abundant Neogene extinct nanoplanktons (Discoaster spp.) until MIS-3 which was transported from the Varkala Formation (highlands of the Kerala coast). The pollen assemblage is comparable to the present day flora in Kerala except Ongokea gore which is now present in South Africa and therefore, the provenance of pollen recorded in the studied core is Western Ghats of India. High percentage of planktic foraminifera and dinoflagellate cysts throughout the core indicates high productivity that suggests upwelling induced by seasonal reversals in the monsoon winds even during the glacial periods. Botryococcus remains and poaceous leaf cuticles dominated by the Pooideae group in the marine realm also point towards active winter monsoon. Considerable fragmentation of rain forest took place post 74ka and during the LGM as the sea retreated to its maximum which resulted into the vast exposure of land favoring the expanse of grassland with pockets of rain forest “plant refugia” on land. Neogene rain forest flora recorded earlier from the Varkala Formation and the present record of its existence since MIS-6 in the region provide an understanding that the monsoon circulation over southern India was similar since the Middle Miocene Climate Optimum and the flora in the South-Western Ghats is a fossil ecosystem and a relic of the Tertiary period.

Palynological contributions to the taxonomy of family Oleaceae, with special empahsis on genus Forsythia (tribe Forsytheae)

Traditionally, the Oleaceae has been divided into subfamilies Oleoideae and Jasminoideae. In the present paper, the taxonomical results so far made on the family were reviewed on the basis of palynology. The subfamilial classification is not well supported palynoligically, because both Myxopyrum of Jasminoideae and Comoranthus of Oleoideae having foveolate surface are well distinguished from the rest of the family having reticulate surface. The recent subfamily Nyctanthoideae (Takhtajan, 1977) including the monotypic Nyctanthus, was suggested to be included within the Jasminoideae although its closest relative on the palynological basis is different from that on the molecular basis. Tribal classification systems of the Jasminoideae are not well supported palynologically on the basis of surface character: presence or absence of bands on the mural ridge surface of the reticulum. On the basis of palynology, tribe Forsythiae including Abeliophyllum, Fontanesia, and Forsythia is monophyletic, and Fontanesia is well distinguished from the rest two. Korean species of Forsythia is divided into two: Forsythia koreana group and F. ovata-nakaii-saxatilis group. Recent discovery of F. saxatilis at a locality of F. ovata raised a question if the distinction between the two species on the basis of hairiness would be right. In the recent molecular studies, F. saxatilis var. lanceolata seems to be identified as F. saxatilis. Molecular studies showed that F. saxatilis (seemingly var. lanceolata or var. pilosa) is close to F. koreana. The fact in which the molecular result showed a close relationship between F. saxatilis varieties and F. koreana, is controversial to the result by floral and vegetative morphology. An intensive taxonomic study of these taxa would be needed.

Cretaceous plant fossils of Pitt Island, the Chatham group, New Zealand

Pitt Island, a part of the Chathams Islands group, lies 700 km east of New Zealand. Its geology includes the Tupuangi Formation, dated as Motuan to Teratan (late Albian to Santonian) on the basis of palynology. Samples of Tupuangi Formation mudstone yielded leaf cuticle assemblages dominated by araucarian and podocarp conifers and locally by angiosperms. The 12 distinguishable conifer taxa include a new species of Araucaria, A. rangiauriaensis, and the extinct genera Eromangia, Kakahuia (both Podocarpaceae), Otwayia (Cheirolepidiaceae), Paahake (Taxodiaceae or Taxaceae) and possibly Katikia (Podocarpaceae). Ginkgo and two types of dicotyledonous angiosperm cuticle are present. Based on the absence of bennettitaleans and rarity of Ginkgo, a Turonian or slightly younger age is inferred, making the Pitt Island assemblage the first Turonian plant macrofossils documented from New Zealand. The fossils provide a window into southern high-latitude (polar) vegetation of the mid-Cretaceous. Conifer charcoal (probably of Podocarpaceae) is locally abundant and suggests that fire was an important part of the ecosystem. A broad analogy with modern boreal conifer-deciduous angiosperm forests is suggested although clearly with warmer temperatures.

Effect of volcanic ash-fall on a Permian peat-forming environment, on the basis of palynology, palynofacies and paleobotany (Faxinal Coalfield, Brazil)

Effect of volcanic ash-fall on a Permian peat-forming environment, on the basis of palynology, palynofacies and paleobotany (Faxinal Coalfield, Brazil)

A new variety of the weed Borreria densiflora DC. (Rubiaceae)

The weed, known commonly as vassourinha de botão (buttonweed), is present in several crops in northern and north‐eastern Brazil. Its occurrence is common in sugarcane and soybean crops in the states of Goiás, Tocantins, and Maranhão. However, there is no published information in the literature about its taxonomic classification. Thus, this research aimed to classify taxonomically this species in order to develop a classification key based on the morphological characteristics among varieties of Borreria densiflora DC., as well as to illustrate it and provide a palynological basis to classify this species as a new variety. For the classification process, data from the literature, morphological characteristics, and palynological evidence were considered. In this article, we describe a new variety, B. densiflora DC. var. latifolia E.L. Cabral & Martins. The new variety possesses a terrestrial habitat and it is a simple perennial weed species. These results show the importance of an accurate identification, as well as an understanding of the evolutionary changes inherent to weeds (like intraspecific variability), breeding system, genetic potential, and ecological studies. Those factors are essential to the beginning of a long‐term weed management strategy.

Tylerianthus crossmanensis gen. et SP. NOV. (aff. Hydrangeaceae) from the Upper Cretaceous of New Jersey

A fossil flower with affinities to the modern families of the saxifragalean complex is described. Fossils were collected at Old Crossman Pit, Raritan Formation, New Jersey, USA. These sediments are dated on the basis of palynology as Turonian (Upper Cretaceous, ~90 million years before present). Fossils are charcoalified and preserved with exceptional three- dimensional detail. The characters observed in these flowers, when compared with those of extant flowers of several families of the saxifragalean complex, suggest a close relationship with extant members of the Saxifragaceae and Hydrangeaceae. Hypotheses on the origin of petals and staminodes and a possible mechanism of pollination are discussed. This new taxon provides additional characters in the floral morphology of the fossil saxifragoids and extends their geographical distribution in the Cretaceous to North America.

Découverte dans le bassinHouiller Sarro-Lorrain du genre Radiitheca (organes reproducteurs de filicophytes) et ultrastructure du genre Microreticulatisporites

A specimen of the fern fructification Radiitheca Brousmiche et al., up to now only known in the Pilsencoalfield (Czech Republic), has been discovered in the late Westphalian D strata of the Sarre Lorraine coalfield. Relationships between Radiitheca dobranyana Brousmiche et al. and Pecopteris waltonii Corsin are discussed both on paleobotanical and palynological basis. TEM study of the Microreticulatisporites (Knox) Potonie & Kremp macerated from the French and Czech specimens led to the characterization of the unique layer of the spore-wall that is the exospore, This investigation has shown: (1) that the ultrastructural features of the spores from both localities are perfectly similar, (2) the nature of the bodies occurring in each lumen that were called “pustules” in Brousmiche et al. (3) and that the lack of these ones is only due to preservation or maceration bias. A comparison of the exospore ultrastructure with that of main groups of living ferns suggests close affinities between the genus Radiitheca and the Gleicheniaceae.

Micropalaeontology and palynology of the Lower and Middle Cretaceous Thamama and Wasia groups, DK-C well, Dukhan oil field, Western Qatar. / Micropaléontologie et palynologie dans le Crétacé inférieur et moyen des groupes de Thamama et de Wasia, puits DK-C, champ pétrolifère de Dukhan, Qatar occidental

Well preserved, diverse sporomorphs, phytoplankton and foraminifers have been found in cores from the DK-C well, Dukhan Oil Field, Western Qatar, Arabian Gulf. Most samples studied contained dinocysts, acritarchs, foraminiferal test linings, spores, pollen grains and benthic and planktic forams. From the entire palynomorph assemblage mainly dinoflagellate cysts and miospores were studied to give a stratigraphie outline for the upper Lower and Middle Cretaceous Thamama and Wasia groups. The age of the Shuaiba Formation as indicated by dinocysts is possibly early Aptian. Deposition took place in a marine environment which could possibly reflect the extreme distal locus of deposition. A tentative late middle Albian age could be assigned to unit A of the Nahr Umr Formation on basis of palynology. However unit В is dated as late Albian by palynomorphs and early Albian by foraminifera. In view of the extremely low faunal recovery and unavailability of samples from unit С of the Nahr Umr Formation, no age assignment could be postulated. The clastic facies of the Nahr Umr Formation showed high recovery of fern spores which allows us to assume marshy environment with fluviatile deposits that phased out Albian sedimentation. The dating of the Mauddud shelf carbonate Formation as late Albian, based on foraminifera, is not supported palynologically. Unit A of the Ahmadi Formation did not yield any diagnostic fauna that did allow an age assignment. The presence of elater-bearing palynomorphs, diagnostic miospores and dinocysts in this interval confined the age of this unit to the late Albian-early Cenomanian. This aspect of the Albian-Cenomanian flora could possibly indicate the prevalence of marine conditions in its upper part and the elaters are suited to a presumed arid or semi-arid climate. Units В, С and D are of early and middle Cenomanian, based on the presence of Hensonina lenticularis and Asterohedbergella asterospinosa zones. The Mishrif shallow water limestone Formation which closes out the Middle Cretaceous with alternations of limestone and shale is attributed to the late Cenomanian Dictyoconella minima Zone reported from adjacent wells in the same region.

Palynostratigraphy of the Upper Cretaceous in Hungary

Within the territory of Hungary four sedimentologically different sequences can be distinguished in the Senonian: the Transdanubian Central Range, the 'Gosau', the flysch and the southern Great Hungarian Plain. The most continuous Central Range sedimentary succession can be referred, on the basis of palynology, to the Upper Sanionian-Upper Maastrichtian, while the deposits of "Gosau-type" are Campanian, and the Bácsalmâs horizons in the southern part of the Great Hungarian Plain can be considered Upper Campanian-Maastrichtian.The geographically remote Pelso and Tisza units belonged to the same, so-called Normapolles Phytogeographic Province during the Late Cretaceous. Senonian sedimentation started in both areas at about the same time. Palynostratigraphic analyses have been carried out on sections within both units. Eight zones, and within them eight subzones, have been differentiated.

Some spores and pollen from the Cullen formation (upper Eocene to middle Oligocene), Tierra del Fuego, Argentina

Abstract The Cullen Formation is exposed in the northeastern part of Tierra del Fuego Island; it is dated as Late Eocene to middle Oligocene on the basis of palynology. In this paper, 21 palynomorphs from the type locality of the formation are recorded, 13 of which have been previously described. Notable taxa include Baculatisporites comaumensis (Cookson 1953) Potonie 1956, Catinipollis geiseltalensis Krutzsch 1966, Crassiorites australis gen. et sp. nov., Lycopodiumsporites eminulus Dettmann 1963, Malvacipollis argentina sp. nov., Nothofagidites suggatei (Couper 1953) Hekel 1972, Phyllocladidites mawsonii Cookson 1947 ex Couper 1953, and Reboulisporites fuegiensis gen. et sp. nov. All of these species can be assigned to extant families with a high degree of confidence. The occurrence of M. argentina and C. australis is consistent with the hypothesis of a southern origin of Malvaceae and Onagraceae.

Dall’Appennino Campano alle Serre Calabre - Cenni palinologici e paleoclimatici

Dall’Appennino Campano alle Serre Calabre — Cenni palinologici e paeloclimatici DARIA BERTOLANI MARCHETTI Istituto e Orto Botaizico deZ[’U7zz'verrz'td dz’ Modem: SUMMARY A reconstruction of the vegetational history on palynological basis was performed in the southern italian peninsula in contest of Mediterranean events starting from the Late Miocene (Messinian). Data of this period are not available for the specific area, but palynological studies in perimediterranean lands and deep sea drillings have provided a valid framework. We can thus hypothesize the previously existing vegetational belts and their shift in altitude following climatic impairment occurring in the Late Messinian. - The plio-pleistocene boundary is important and much discussed. It leads to marked glacial events, which follow others ones occurring during the Late Messinian and the Late Pliocene. Interesting sequences are those at Vrica et «Le Castella». The former has been proposed as the stratotype of the Pliocene-Pleistocene transition. Recent researches indicate that the latter is completely of pleistocene age; the basal belt changes from a mediterranean «Macchia-gariga» to a steppe vegetaton, and then perhaps evolves to a light forest of thermophylous hardwoods, with an overhanging coniferous belt. Continental Italy was subjected to the well-known events of alpine glacials during the Pleistocene, whereas the peninsular part should belong to that area of the Mediterranean whose glacial periods are pluvials (Greece, Israel etc.). The presence of mountainous areas along the peninsula and of at least one large lacial center at Gran Sasso induces northern-like conditions. Microtermic elements from Central Europe (Bryop/ayta and P/mzzerop/Jyta) must have migrate in the glacials or stadial along Apennine «cool routes». Absolute dating relative to the Canolo Nuovo (Calabria) diagram places it in the last glacial, late glacial and postglacial. This diagram does not contain evidences of glacials with forest and interglacials with steppic mediterranean conditions but is more closely related to Apennine mountains, having Alpine climatic influences and vegeta- tional features of the forest cycles stated from Chiarugi for the Tuscan Apennines. Similar analogy, with delayed cycles, occurs in the diagrams of Lucania and Abruzzo. Palynological researches has confirmed in the southern part of the peninsula the already known events of Alfie: and Fzzgur, the behaviour of A/mz: irzcazza, and once again the indigenous quality of the Chestnut. INTRODUZIONE Per la ricostruzione delle passate vicende climatico-forestali le ricerche palinologiche, sempre piu affinate, hanno raggiunto un tango di primaria irnportanza. Gli spettri polliruci hanno, come e noto, 1l vantaggio di fornire dati statisticarnente accettabili e riguardanti territori abbastanza ampi e piani altirne- ‘ trici diversi, pur con tutte le difficolta di interpretazione, per la quale si richiede una certa esperienza e una dotazione di conoscenze delle formazioni vegetali anche a livello extraeuropeo. Lo studio delle filliti e di altri macrofossili, che ebbe un grande sviluppo in passato e che tnostra ora recenti sintomi di ripresa, mette molto spesso in evidenza situazioni piu strettamente locali, ecologicamente inquadrate in condi- zioni rnicroclimatiche tendenzialrnente conservative e sottraenti la vegetazione 67

Some paleoclimatical and paleovegetational features of the Messinian in the Mediterranean on palynological basis

Si espone una sintesi delle ricerche finora note sul Messiniano (Miocene Superiore) nell'area mediterranea, con qualche notizia marginale sul sottostante Tortoniano. La crisi di salinità messiniana è sempre stata considerata estremamente grave per la vegetazione. Si profila però ora un peggioramento del clima considerato drammatico nell'oligocene con clima glaciale ed ampliamento delle calotte polari. Nell'Italia Settentrionale esistono ricerche sulla formazione gessoso solfifera nelle colline presso Bologna. Negli interstrati marnosi si hanno accenni di ambiente palustre costiero, una stretta fascia di latifoglie termofile, una sovrastante fascia di conifere abbassata di quota dal deterioramento del clima. L'alternanza ritmica di bancate gessose e marnose sembra legata ad oscillazioni climatiche; le analisi polliniche mostrano un progressivo raffreddamento dalla base al tetto di ogni interstrato marnoso. Un livello basale, a contatto col Tortoniano, dovrebbe dare un'immagine della vegetazione all'inizio del Messiniano, che testimonia un clima nettamente più caldo dei livelli sovrastanti. Un giacimento a Carbonara Scrivia (Alessandria) ha filliti e pollini sui quali non è stata effettuata analisi, per il quale si è ipotizzato un clima temperato-caldo con variazioni ecologiche locali. Palinologicamente non utilizzabili sono ricerche condotte nella pianura lombarda per il drastico pretrattamento subito dai campioni, che può aver oltre tutto prodotto una selezione dei granuli in base alla resistenza del loro sporoderma. In Toscana il giacimento di Gabbro (Livorno) ha abbondanti filliti e un ricco contenuto in pollini, determinati con metodo formale e attribuiti poi per affinità a genere o specie. Il clima appare piuttosto secco, subtropicale; le igrofite del piano basale vivono in acque salmastre o lungo corsi d'acqua, mentre allontanandosi dalla linea di riva e alzandosi di quota si trovano foreste a Pino, Sequoia e Querce, poi formazioni arboree rade e savane con querce sempreverdi ecc. Per la Sicilia si hanno dati palinologici per sedimenti di una miniera presso Caltanissetta, che mostrano una maggiore termofilia di quanto riscontrato per i gessi bolognesi. Una sequenza Tortoniano-Messiniana presso Falconara ha solo testimonianze di distribuzione in fasce altitudinali con pollini di conifere giunti da lontano, piuttosto che di un peggioramento climatico, limitatamente alla parte premessiniana. Si hanno dati per l'Andalusia (Spagna meridionale) non sufficienti per la ricostruzione della vegetazione. Ricerche palinologiche datate (6.4 ± 0.2 M.Y. b.p.) nell'Ardèche, Francia mostrano un clima piuttosto arido e caldo. Molto dettagliati sono gli studi palinologici nelle evaporiti messiniane di Paghi presso Corfù in Grecia; ritroviamo anche qui la fascia di conifere superiore sovrastante ad una stretta fascia di querceto, nel quadro di un clima mitigato. La composizione «moderna» della flora del Messiniano è constatata in studi palinologici inerenti al Neogene della Turchia, mentre dati di Jaffa in Israele riguardano solo la fase precedente quella evaporitica e rivelano clima caldo e secco. Le analisi condotte in campioni del DSDP nel bacino levantino e in quello balearico mostrano clima moderatamente caldo premessiniano e piuttosto fresco all'inizio del Pliocene. Al sito 132, nel Tirreno, l'abbondanza di reperti palinologici permette di ricostruire quattro piani di vegetazione, che hanno servito per base allo schema di Boquet e che concordano coi reperti del Gabbro, con piante più o meno igrofite nel piano basale, una stretta fascia di latifoglie termofile, e una di conifere, ribassata verso livelli inferiori dal peggioramento del clima. Il Messiniano sembra aver avuto nel Mediterraneo una prima parte più calda e asciutta e una seconda più fresca e umida; questo ovviamente in linea generale e con le variazioni che possono essersi verificate ad esempio in locali microambienti. A completamento di quanto esposto sulle ricerche palinologiche vengono ricordati altri contributi non paleobotanici che possono essere molto validamente utilizzati per le ricostruzioni paleoclimatiche. Si tratta delle ricerche sui piccoli roditori, che già hanno permesso di costruire interessanti curve climatiche. Di recente, sono stati condotti studi sui minerali delle argille (smectite, illite, clorite, ecc.) la cui formazione è influenzata dalle condizioni climatiche sul Messiniano e su altri periodi soggetti a importanti cambiamenti ecologici richiedono una ben coordinata integrazione fra i diversi rami della scienza.

Some results of palynological investigation on Severnaya Zemlya in relation to the question of the transport of pollen and spores in the high Arctic

Abstract The authors carried out palynological analyses of ten surface samples from October Revolution Island (Severnaya Zemlya). They also trapped airborne pollen and spores on the Vavilov Ice Cap. Tree pollen (from pine, spruce, alder, birch, and in one case lime) was well represented in all samples, although the local vegetation is that of various tundra associations. The results reinforce the dangers implicit in reconstruction of Pleistocene environments on the basis of palynology in the High Arctic.

The palynological basis for the triphyletic theory of angiosperms

Abstract The pollen grains and spores constitute an important morphological entity, reflecting the facts and facets of plant evolution. Among the various characters of the exine, the aperture is considered to be the most conservative. The grains are primorphous (apertures indistinct) in Thallophyta, trimorphous (trilete, monolete and alete) in Archegoniatae and polymorphous (colpate, colporate, porate, etc., the apertures varying in number and form), in the angiosperms. The trimorphous condition is characteristic of the preangiospermous Archegoniatae, and its occurrence in the angiosperms may be considered to provide an indication of the primitive taxa of the group. Against this background, it is argued that the angiosperms are triphyletic, having three independent phylogenetic stocks, namely the Monocot stock, the Magnolian dicot stock, and the Ranalean dicot stock, in that order of phylogenetic succession