This special volume of the Earth and Environmental Science Transactions of the Royal Society of Edinburgh compiles key papers presented at the 4th International Agora Paleobotanica Meeting, which took place at the National History Museum of Brussels, 7–9 July 2016. Agora Paleobotanica is an international association that promotes research and acquisition of knowledge in all fields of palaeobotany and palynology. This association, originally formed by researchers of southwestern Europe, currently includes worldwide teams and puts a special emphasis on young researchers. The 2016 meeting had 45 delegates presenting 29 abstracts. This special issue comprises 11 articles covering a wide variety of plant groups, ranging from the Devonian to the Miocene, and including both megafossils and plant microremains.

Three papers are dedicated to the Paleozoic Era. They describe Devonian material and provide new data about the early diversification of land plants and the earliest forested ecosystems. Cascales-Miñana et al. (2018) document a new highly diverse palynoflora from the Lower Devonian Posongchong flora (SW China), including a new Aneurospora species, and point at important differences of plant diversity between Gondwanan and Laurussian floras. Orlova et al. (2018) redescribe Kossoviella timanica Petrosjan, a Frasnian (Upper Devonian) heterosporous lycopsid from Russia, which improves our knowledge about the early evolution of those important plants. Tanrattana et al. (2018) describe a new Callixylon species (Archaeopteridales) from the Famennian of Mader el Mrakib (Morocco). This new Callixylon evidence increases the geographical distribution of the taxon and suggests that northern Gondwana may have been favourable to the establishment of diverse communities of these early trees.

Six papers explore the Mesozoic plant fossil record. Harper et al. (2018) provide a detailed study about three different fungal remains found in a fern. This study, based on Triassic material from Germany, depicts for the first time the fungal distribution throughout a large portion of a fossil plant. Ríos-Santos & Cevallos-Ferriz (2018) provide a set of anatomical analyses of several wood remains from the Jurassic to the Paleocene from Mexico and describe, among others, new Agathoxylon and Taxodioxylon species. Liu et al. (2018) report on Zhangwuia, an unexpected plant fossil organ from the Jurassic of China that probably represents an intermediate link between the Bennettitales and the angiosperms. Estévez-Gallardo et al. (2018) provide new data from the Albian (Lower Cretaceous) of the Iberian Peninsula. They show the first evidence of plant–insect interaction with aquatic angiosperms belonging to the genera Plufolia and Aquatifolia (Nymphaeales). Sender et al. (2018) show new evidence of Tempskya, an extinct tree fern, from Albian deposits of Iberian Peninsula, which contributes to fill the distributional gap of this fern during the Early Cretaceous in Eurasia. Gomez et al. (2018) present a new locality with silicified permineralised evidence belonging to Geinitzia (Coniferales) and ‘Lomatopteris' superstes (angiosperm eudicot) from the Turonian (Late Cretaceous) of France.

Finally, two papers report recent Cenozoic investigations. New data on Icacinaceae are documented by Del Rio et al. (2018), who describe five new Iodes species from the Paleocene Rivecourt deposits (France). Hernánde-Damián et al. (2018) describe Staphylea ochoterenae, a new species from Miocene amber of Mexico, representing the first fossil record of a Staphyleaceae flower.