Taxonomy of the Paeonia delavayi complex (Paeoniaceae)

The Paeonia delavayi complex, a group of woody peonies endemic to China, is problematic because of the lack of agreement among the taxonomic treatment s of the group. Some taxonomists recognize one species with three intraspec ific taxa, while others accept only two species, and yet others accept thre e species with two intraspecific torn. The present paper is based on extens ive field observations, population sampling, and analysis of certain charac ters. The results show that the complex is extremely variable both within a nd between populations in the number, length, and width of leaf segments an d in number, size, and color of all the floral parts. This variation is con tinuous, and there is no correlation between the characters. Only one speci es, P. delavayi, is recognized, without infraspecific taxa. Paeonia lutea. P. potaninii, and their infraspecific names are reduced to synonymy of P. d elavayi. Vegetative reproduction by stolons is predominant in this variable species, and the roots are thickened fusiformly. These two features probab ly facilitate adaptation to open and somewhat dry habitats, and allow for r apid colonization whenever plants become established. Although P. delavayi has been listed as endangered, it is unlikely to become extinct if wanton d igging is controlled.