Taxonomic diversity, biology and ecology of leaf endophytes were studied from some evergreen plants including Arbutus unedo, Buxus sempervirens, flex aquifolium, Laurus nobilis, Ligustrum vulgare, Prunus lusitanica, Rhododendron ponticum, Rhododendron sp., and Skimmia sp. from England, and some others from China. It was found: 1. A great number of fungal species, including several new species and new British records, have been isolated. Distribution patterns of endophyte assemblages and their variations between plant species and geographical locations are described. 2. Comparisons of leaf endophytes and saprobes of R. ponlicum at the same locality showed they belonged to two different ecological groups. This was further confirmed by study on endophytes and saprobes from a number of plant species growing in the same locality. 3. Host specificity of endophytic fungi at the species level was rare and this was supported by comparisons of endophyte assemblages from both taxonomically related (same family) and unrelated (different families) plant species. Molecular characterisations of Phyllosticta species confirmed this. 4. Infection and colonisation studies during a two year period showed that leaf endophytes of R. ponlicum were horizontally transmitted. Internal bud material was sterile and became infected by aerial spores. The infection and colonisation level of endophytes were strongly affected by environmental conditions. 5. Phylogenetic studies of Phyllosticta based on ITS 1-5.8s rDNA-ITS2 sequences concluded there was no evidence to show that the evolution of host plants of Phyllosticta species and ITS were related. Most Phyllosticta species from the same locality were found to have a broad host range and occurred on many taxonomically unrelated plants in the same locality. P. concentrica was separated into 4 species including P. concentrica on Hedera, P. arxii on Ilex, P. maxima on Rhododendron and P. taxi on Taxus.