Abstract
This chapter reviews aspects of diversity of endophytic fungi: how sampling strategies affect results of diversity studies; how communities of endophytic and epiphytic fungi differ in a single leaf; how endophytic fungi vary from leaf to leaf; how endophytes are transmitted; and how endophytes may affect other microorganisms (including plant pathogens) and host plants. It focuses principally on literature published since Phyllosphere 2000 and on tropical plants. The genus Xylaria is used as an example of differences between endophytes of tropical and temperate plants, and of unresolved problems of diversity and distribution of endophytes. Although the chapter focuses on endophytic fungi, examples from epiphytes, bacteria and temperate endophytes are also included, because their diversity is better understood in many respects. It concludes that a more integrative approach is needed to understand the diversity and importance of phyllosphere microorganisms.