Bryophyte disjunctions in the Northern Hemisphere: Europe and North America*

Two major disjunctions are recognized between the bryofloras of Europe and North America: Amphi-Atlantic and Western Europe—Western North America. Each of these has specifically segregated floras related to climatic regimes and correlated with different historical development. An interpretation of the disjunctions is based on reconstruction of past continental interconnections coincident with reconstructed climates and an understanding of the biology of the bryophytes.