A new angiosperm genus is recognized based on complete plants preserving roots, stems, linear leaves, inflorescences and infructescences from the late part of the early Eocene of western Colorado, USA. The plants of Kohlsia parachutensis gen. et sp. nov. measure 5–8 cm in height, and are characterized by an apparent basal rosette of alternate leaves and a short main axis terminated by a racemose inflorescence with lateral racemose inflorescences arising alternately. Based on the short stature, heterophyllous leaves, and depositional context we infer that it was potentially a rooted semiaquatic. The fused hypogynous perianth of five tepals and single-seeded fruits lead us to consider it likely to be a superasterid, but its ordinal and familial affinities remain obscure. Kohlsia is a rare example of an herbaceous angiosperm from the Green River flora.
The fossil seed, Decaturospermum macrocarpum (Lesquereux) gen. nov. et comb. nov., is described based on specimens of latest Albian to mid-Cenomanian age (mid-Cretaceous) from the Dakota Formation of Nebraska, and Kansas, USA, which were previously named Laurus macrocarpa Lesquereux; and from the Woodbine Formation of Texas, USA, which were previously named Laurocarpum tetragonale MacNeal. All specimens are molds and casts lacking cellular details, but light microscopy and micro-CT scanning reveal key structural features. Combined information from eight specimens indicates that D. macrocarpum is a seed with an outer covering comprised of four valves. The four valves are reflected in the cast of the seed cavity, which has a quadrangular transverse section with four rounded edges. Each valve has a smooth outer surface covering a decay-susceptible outer layer that was replaced by sediment early during fossilization. Sediment filling the space left by the decaysusceptible outer layer preserves an impression of a distinctive dendritic reticulate system of longitudinal and transverse ribs on its inner surface, which reflects the outer surface of a decay-resistant inner layer, now seen only as a cavity. The inner surface of the decay-resistant inner layer is smooth, as is the outer surface of the cast filling the seed cavity. Below the seed cavity a downward extension of the decay-resistant layer forms a prominent swollen-cylindrical flange around the seed base. Decay-susceptible tissues inside the swollen flange are replaced by sediment but preserve the distinctive sinuous course of four vascular bundles. The position of each bundle suggests that it entered a valve in a near median position. Comparison of Decaturospermum macrocarpum with other seeds of Cretaceous age indicates that the two-layered, four-valved outer covering is the envelope of a chlamydospermous seed, which was most likely produced by plants closely related to extant Gnetales.
Five sediment cores were collected from Lake Krzywce Wielkie (‘Bory Tucholskie’ National Park) to reconstruct macrophytes succession: four from the littoral zone (35 cm) and one from deep water. Chronology originally published by Milecka and co-authors was established using radiocarbon dating for the deep-water core and short-lived isotopes for the littoral cores. Initial estimates suggested that the upper 13–20 cm of littoral sediments represented the last century; however, inconsistencies in 210 Pb and 137 Cs dating, combined with pollen evidence of sedimentary gaps, necessitated a revision of this timespan. Principal Coordinates Analysis was applied to align pollen sequences from littoral cores with those from the deep-water core, which has a wellestablished 14C-based chronology. Twenty-five biplots representing three datasets (ALL set – all terrestrial taxa; PB set – terrestrial excluding Pinus and Betula ; NAP set – herb taxa) and various core combinations facilitated the development of a revised chronology. Palynostratigraphic correlation provided tentative yet robust age estimates and revealed substantial sedimentary gaps – exceeding one millennium in one core and approximately two centuries in others. Three cores exhibited similar sedimentation patterns, distinct from the fourth. Overall, the chronological addendum presented by Milecka and co-authors demonstrated that littoral sediments are considerably older than indicated by isotope dating.
In Upper Carboniferous Euramerican floras, the generic affinities of enigmatic, cuneate to flabellate “Ginkgo-like” leaves remain poorly understood. The species Cordaites grandifolius (USA), Noeggerathia flabellata (U.K.) and Ginkgophyllum delvalii (Western and Central Europe) have been taxonomically studied and compared, but no formal reclassification nor assessment of the North American form in relation to the European specimens has been conducted prior to this study. Reinvestigation of the holotypes and additional material of these species indicates that they do not conform to their current generic assignments on the basis of laminar morphology, axis structure and paleogeographic range. Here, we synonymize the three aforementioned species under the name Ginkgophytopsis flabellata , which we also emend. This study summarizes the complex taxonomic history of some of the Late Paleozoic “ginkgophytes,” and we also emend the genus Ginkgophytopsis on the basis of our morphological reassessment of G. flabellata .
The early Paleocene was a time of dramatic ecological transformation following the Cretaceous–Paleogene (K–Pg) mass extinction. Although terrestrial recovery has been well-studied in the Western Interior of the United States, macrofloral records from early Paleocene Canada remain sparse. Here, we describe a diverse early Paleocene fossil plant assemblage from the Ardley Coal Zone of the Scollard Formation at the Highvale Coal Mine in Alberta. The flora includes 27 leaf, fruit, and seed taxa and is composed of ferns, conifers, and broadleaf angiosperms preserved in floodplain and swamp deposits lying about 14 m above the K–Pg boundary. We present new taxonomic descriptions alongside quantitative palaeoclimate reconstructions using leaf physiognomic and Nearest Living Relative methods. These estimates, synthesized via an ensemble approach, indicate that Highvale supported a warm-temperate (mean annual temperature of 9.6°C), humid forest (relative humidity at 76.8%) with moderate seasonality (driest month precipitation at 4 cm) and moderate net primary productivity (701 gC m−² yr−¹). These results are compared to those from the broadly coeval Genesee and Ravenscrag fossil floras, which reflect a latitudinal climate gradient and localized environmental variation during the early Paleocene in western Canada.
