XVI International Botanical Congess

Recent synthetic phylogenetic analyses suggest that desiccation tolerance was primitively present in the bryophytes (the basal-most living clades of land plants), but was lost in the evolution of tracheophytes. However, at least one independent evolution (or re-evolution) of desiccation-tolerance occurred in Selaginella and in the ferns. Within the Angiosperms, at least eight independent cases of evolution (or re-evolution) of desiccation-tolerance occurred. The time scale of desiccation, rehydration and responsiveness are different in different lineages. We map these phenotypic expressions of desiccation tolerance onto the most recent cladograms, and look for ecological/biogeographic correlates.