A molecular phylogeny and a new classification of Pyrola (Pyroleae, Ericaceae)

The northern temperate genus Pyrola L. is the largest and arguably the most taxonomically complex element in the tribe Pyroleae (Ericaceae). Here we present a molecular phylogenetic study with extensive sampling comprising 26 ingroup and 7 closely related taxa. The results, based on parsimony and Bayesian analyses of nuclear (ITS) and chloroplast (atpB-rbcL, trnS-trnG, trnL-trnF) DNA sequences, add substantially to our understanding of relationships within this diverse group and call for taxonomic changes. Pyrola is confirmed as a monophyletic group with two redefined sections and six series: P. sect. Pyrola (P. ser. Pyrola, ser. Ellipticae and ser. Rugosae) and P. sect. Scotophylla (P. ser. Japonicae, ser. Scotophyllae and ser. Chloranthae). Members of each respective section and series share similar morphological traits and/or geographical distributions. For the potential hybrids P. media and P. faurieana, the maternal donor was identified by their close affinity to P. minor in the chloroplast trees whereas the paternal donor remained unclear.