XVI International Botanical Congess

Seventy living populations conforming vegetatively to Porella canariensis, P. cordaeana, P. inaequalis and P. obtusata were analysed using isozyme methods to assess patterns of genetic differentiation within this complex in Madeiran archipelago. Analysis of vegetative characters considered to be taxonomically informative for Porella taxa were taken into account. On the basis of 11 loci, 50 different genotypes were recognized among the 4 species. The % of polymorphic loci per species varies in between 0% (P. inaequalis) to 90.91% (P. canariensis). P. canariensis appears genetically and morphologically more complex than the 3 other species and can be subdivided into 3 different groups, supported by the values of genetic distances. Even in polymorphic species such as P. canariensis, the partitioning of gene diversity is between rather than within colonies.