Abstract A database of all reported Ordovician–Silurian land plant megafossil and dispersed spore assemblages has been assembled. For each assemblage a list of taxa has been prepared and its location plotted on new palaeocontinental reconstructions. These new data compilations are analysed with respect to palaeophytogeographical differentiation and various patterns of taxon diversity and morphological disparity that emerged during the origin, adaptive radiation and geographical spread of land plants. Our analyses include new quantitative assessments. Supplementary material: Appendix consisting of an abridged version of our dispersed spore database is available at: http://www.geolsoc.org.uk/SUP18680