Palynology and palynofacies patterns of terrestrial Triassic/Jurassic boundary series of the South Hungarian Mecsek Mountains were studied in search of paleoenvironmental and vegetation changes and climatic signatures related to one of the major mass extinction events in Earth's history. Two selected and studied boreholes comprise continuous boundary sections and yield a diverse Late Rhaetian to Hettangian palynomorph assemblage. The most striking feature within the boundary interval is the series of cyclic short-term paleoenvironmental changes from fluvial/deltaic to swamp settings, as inferred from changes in palynomorph associations. However, increasing humidity is documented by a striking increase in trilete spores. These signatures display the response of terrestrial vegetation to regional and global environmental changes, although we found no clear evidence for a mass extinction as documented in the microflora.