Communities of endophytes inhabiting a particular host may beubiqui-tous, or have what is frequently referred to as host specificity .Weconcur with Carroll (1999) and Zhou and Hyde (2001) that the term “specificity” should be reserved for organisms that will only grow in one host . If this is not the case, this phenomenon could be termed host preference or host-exclusivity . Whether the interaction represents specificity, preference or exclusivity, an adaptation of host and endophyte to one another has occurred. The adaptation may not only be to a particular host, but to endophytic growth in one plant organ, e.g. in the roots in contrast to the shoots