Identification of oligoclonal agamospermous microspecies: Taxonomic specialists versus microsatellites

There has been a decrease in the ability of biologists to identify their material correctly, particularly plants of complicated genera with common agamospermy, where old clonal entities are accorded the rank of species (microspecies). Agamospermous microspecies are taxonomic entities recognizable from one another by a set of minute morphological features. The knowledge of microspecies is confined to a few specialists. Specialists use microspecies names but there could be inconsistencies in the taxonomic concepts used by different, geographically remote experts. A selection of nine widespread, generally recognized agamospermous microspecies of Taraxacum sect. Taraxacum, which are characterized by means of eight microsatellite loci, were used to evaluate the ability of four European Taraxacum specialists to identify these microspecies consistently. With two exceptions (and one unclear result) for 125 plants coming from an area extending from Finland to central Europe, the experts identified the microspecies consistently, exclusively on the basis of morphological differences. Another problem studied was within-species variation. The within-species microsatellite variation corresponded to the mutational clone cluster hypothesis, with a single unclear result. Each microspecies consisted of one, more or less dominant, clone and several minority clones, each usually confined to a single plant. A combination of the traditional microspecies identification by experts and the characterization of microspecies by a set of molecular markers opens the field of microtaxonomy to a wider group of researchers.