The studies presented in this paper analyse diversity patterns of land plants (mosses, ferns, gymnosperms, and angiosperms) at continental to global scales. A revised version of our earlier world map of vascular plant species richness and the first maps of species richness of mosses and gymnosperms on a global scale are presented. Diversity patterns of vascular plants are correlated with different measures of geodiversity (the diversity of the abiotic environment). Global centres of vascular plant diversity coincide with highly structured, geodiverse areas in the tropics and subtropics. These are the Chocó-Costa Rica region, the tropical eastern Andes and the north western Amazonia, the eastern Brazil, the northern Borneo, and New Guinea, as well as the South African Cape region, southern Mexico, East Himalaya, western Sumatra, Malaysia, and eastern Madagascar. Constraints imposed by the physical environment, such as the length of the thermal vegetation period or water availability, shape large scale trends of biodiversity. However, important centres of species richness and endemism can only be explained when taking into account the history of the floras. The main diversity centres in SE Asia are the same for gymnosperms as for all other vascular plants, but in other parts of the tropics and subtropics there is low gymnosperm diversity. The exceptions to this pattern are Mexico and California, which have almost as many species of gymnosperms as SE Asia. The increase in the number of species and genera published during the last 250 years is documented, based on data from the Index Kewensis. The first continental maps of Cactaceae diversity at species and genus level are used to show how choice of the taxonomic level affects the analysis and its implications for priority setting in biodiversity conservation. In this context, global biodiversity hotspots are discussed and an alternative world map of hotspots is proposed.