Taxonomy of prickly juniper (Juniperus oxycedrus group): A phytochemical-morphometric combined approach at the contact zone of two cryptospecies.

Based on different essential oil composition paralleling different genotypes, Juniperus deltoides was recently segregated from Juniperus oxycedrus. Despite a clear phytochemical and molecular differentiation, J. deltoides resulted not clearly morphologically discernible from J. oxycedrus, so that it was defined as a cryptospecies. Italy represents the contact zone of their distribution, but the ranges of the two species are not sufficiently known, due to unsatisfactory morphological characterisation. To further complicate the picture, a third closely related species (ecotype), J. macrocarpa, occurs all across the Mediterranean coasts. After a preliminary phytochemical analysis to ascertain the (chemo-)identities of the studied populations, we performed a morphometric investigation to test the degree of morphological distinctiveness among the taxa. According to our analysis, some character (e.g. leaf mucro length, leaf width, seed-cone size and seed size) resulted useful to discriminate these cryptic taxa. Finally, based on these characters, an extensive revision of herbarium specimens allowed us to redefine the distribution pattern of the investigated species in the Central Mediterranean area.