GENETIC-VARIATION IN ORCHIS-PAPILIONACEA (ORCHIDACEAE) FROM THE CENTRAL MEDITERRANEAN REGION - TAXONOMIC INFERENCES AT THE INTRASPECIFIC LEVEL

The genetic differentiation of Orchis papilionacea from Italy, Corsica , Sardinia, Sicily, and Greece was analyzed by isozyme studies. No sig nificant differences at any of the 28 loci tested were observed betwee n samples of the putative subspecies papilionacea from Italy, grandifl ora from Sicily and heroica from Greece, or by comparing sympatric pap ilionacea-like and grandiflora-like subsamples from Sardinia and Corsi ca. The genetic relationships found among the populations studied refl ect more their geographic origin than their taxonomic assignment; papi lionacea, grandiflora, and heroica are, therefore, at least in the stu dy area, not to be considered as subspecies, but as simple morphs, con trolled by few genes (possibly two) with Mendelian inheritance. The ge netic divergence observed among the samples studied is very low and co nsistent with that of geographic populations of a single cohesive gene pool, linked by a high gene flow (Nm = 5.9).