Abstract: Permian palynostratigraphic schemes are used primarily to correlate coal- and hydrocarbon-bearing rocks within basins and between basins, sometimes at high levels of biostratigraphic resolution. Up to now, their main shortcoming has been the lack of correlation with schemes outside the basins, coalfields and hydrocarbon fields that they serve, and chiefly a lack of correlation with the international Permian scale. This is partly because of phytogeographical provinciality from the Guadalupian onwards, making correlation between regional palynostratigraphic schemes difficult. However, local high-resolution palynostratigraphic schemes for regions are now being linked either by assemblage-level quantitative taxonomic comparison or by the use of single well-characterized palynological taxa that occur across Permian phytogeographical provinces. Such taxa include: Scutasporites spp., Vittatina spp., Weylandites spp., Lueckisporites virkkiae , Otynisporites eotriassicus and Converrucosisporites confluens . These palynological correlations are being facilitated and supplemented with radiometric, magnetostratigraphic, independent faunal and strontium isotopic dating.

Abstract: Separate biostratigraphical schemes have been developed for Permian macrofloras in the five main phytochoria (palaeokingdoms), reflecting the essential lack of overlap in taxonomic composition. In Europe two biozones are normally recognized, in North America three zones, in Cathaysia three or four zones, in Gondwana four zones and in Angara five zones. The stratigraphical resolution tends to be far less than that of palynology, and up to an order of magnitude coarser than the macrofloral biozones of the Pennsylvanian subsystem. This is probably due, at least in part, to the lack of rigor in the way that the Permian macrofloral zones have been defined. Nevertheless, the existing zones do provide evidence of the overarching trajectory of change in vegetation through the Permian Period, as it responded at all palaeolatitudes to a combination of climate change, large-scale volcanic eruptions and tectonically driven landscape changes.

Abstract A siliceous permineralized peat block recovered from Hopen in the Svalbard archipelago hosts a low-diversity Late Triassic flora dominated by autochthonous roots and stems of bennettitaleans and lycophytes, and parautochthonous leaves, sporangia, spores and pollen from a small range of pteridophytes and gymnosperms. Some parenchymatous bennettitalean root cells show interactions with chytrid fungi and bacteria; the remains of other fungi and fungi-like organisms are dispersed within the peat’s detrital matrix. Cavities excavated through some roots and compacted detritus contain abundant coprolites probably derived from sapro-xylophagous oribatid mites, although no body fossils have yet been identified. Sparse larger coprolites containing leaf fragments attest to the presence of invertebrate folivores in the ancient ecosystem. The low-diversity flora, relatively few trophic levels and simple nutritional web, together with sedimentological aspects of the host formation and the peat structure, collectively favour accumulation of the organic mass as a fibric (root-dominated) peat within a temperate (high middle-latitude), well-aerated mire.

We review the extensive record of plant fossils before, at, and after the Cretaceous-Paleogene event horizons, recognizing that key differences between plants and other organisms have important implications for understanding the patterns of environmental change associated with the Cretaceous-Paleogene event. Examples are given of the breadth of prior environmental conditions and ecosystem states to place Cretaceous-Paleogene events in context. Floral change data across the Cretaceous-Paleogene are reviewed with new data from North America and New Zealand. Latest Cretaceous global terrestrial ecology was fire prone and likely to have been adapted to fire. Environmental stress was exacerbated by frequent climate variations, and near-polar vegetation tolerated cold dark winters. Numerous floristic studies across Cretaceous-Paleogene event horizons in North America attest to continent-wide ecological trauma, but elsewhere greater floral turnover is sometimes seen well before the Cretaceous-Paleogene boundary rather than at it. Data from the Teapot Dome site (Wyoming) indicate continued photosynthesis, but during or immediately after the Cretaceous-Paleogene event, growth was restricted sufficiently to curtail normal plant reproductive cycles. After the Cretaceous-Paleogene transition in New Zealand, leaf form appears to have been filtered for leaves adapted to extreme cold, but at other high-southern-latitude sites, as in the Arctic, little change in floral composition is observed. Although lacking high-resolution (millimeter level) stratigraphy and Cretaceous-Paleogene event horizons, gradual floral turnover in India, and survival there of normally environmentally sensitive taxa, suggests that Deccan volcanism was unlikely to have caused the short-term trauma so characteristic elsewhere but may have played a role in driving global environmental change and ecosystem sensitivity prior to and after the Cretaceous-Paleogene boundary.

The biogeographic affinities of the Florissant flora are in need of reevaluation. We give a critical review, based on megafossil and pollen records representing genera whose affinities we accept as well founded. The Florissant assemblage includes taxa of diverse modern geographic distribution. The flora is composed mainly of Laurasian elements, some of which are now confined to Asia ( Ailanthus , Dipteronia , Eucommia , Platycarya , Pteroceltis ) and a wide number co-occurring in the eastern United States and Asia. Others are now confined to western North America ( Sequoia , Cercocarpus , Sarcobatus ) and many occur in Mexico. The major geographic affinities of the Florissant genera discussed here are broad and include the present-day warm temperate and subtropical floras of Mexico, central and southern China, and the southeastern United States. Many taxa appear to have been shared between North America and Asia by Eocene time. The Rocky Mountain flora was distinct from that of the southeastern United States, probably because of the barrier represented by the Cannonball epeiric sea that traversed the Midcontinent in the Paleocene. Similarity of Florissant taxa to the South American flora is low. The deterioration of climate after the time of Florissant deposition represents one of the most significant decreases in temperature of the entire Tertiary. Following the warm interval of the latest Eocene, a few Florissant genera were locally extirpated, a few became extinct, some were already at or dispersed to lower-elevation regions, and others persisted in the southern Rocky Mountains. Over longer geologic time spans, some taxa seem to have persisted on the West Coast of North America through the Miocene, and in a few cases even up to the present. Many deciduous taxa have persisted in the summer-wet climate area of the eastern United States.