Isolated bacteria firstly were grouped using classical microbiological methods, and than were distinguished by 16S rDNA restriction analysis. One strain from each group of Gram-negative bacteria underwent succeeding phylogenetic analysis. Microbial community of the epiphytic orchid distinguished from that of the terrestrial one: the most common microbes of terrestrial P. appletonianum were Gram-positive strains of Streptomyces and Bacillus, while the dominants of epiphytic Ph. articulata roots were Gram-negative Pseudomonas and Flavobacterium ( Table 1). Bacterial rhizoplane diversity of Ph