A method is described for the selective amplification of single mycobiont rDNA sequences from vegetative, non-ascomatal material of the lichenized thalli of Parmelia sulcata and P. saxatilis. The method includes a simple DNA extraction procedure employing rhizines, which avoids the use of liquid nitrogen disruption methods and phenol based extractions. The resulting amplified DNA is suitable for restriction enzyme analysis, and can be used to provide material for investigating population distribution and species concepts.