Disjunctions in Bryophytes

Abstract

In spite of the more general distribution of many bryophytes, dramatic disjunctions exist, many of them similar to those shown by vascular plants.Various explanations have been offered to explain these disjunctions including continental drift, kasdi dispersal, and the fragmentation of a once more continuous distribution.No single ypothesis is sufficient to accommodate all species within any Apert EK e most serious difficulty is the cip i of exploration o ous bryophyte lenis are mapped in E distributinn maps, and details of sexual món rand dispersal mechanisms are assesse Most bryophytes are widely distributed.In the Northern Hemisphere more than 60% of the flora of arctic and boreal regions is made up of the same species.Within this wide range, however, each species has highly specific requirements and some are exceedingly local.Because bryophytes have air-borne diaspores their means of dissemination would appear to guarantee a wide distribution of all species.That disjunctions exist at all would seem somewhat anomalous, yet such disjunctions do exist, some of them very dramatic.The explanation of these disjunctions has led to numerous intriguing hypotheses, many of which have been derived from similar studies of flowering plant disjunctions.In North America the disjunctions that have received the greatest attention