Distribution and synonymy of Plagiochila punctata (Taylor) Taylor, with hypotheses on the evolutionary history of Plagiochila sect. Arrectae (Plagiochilaceae, Hepaticae)

For a long time, Plagiochila (sect. Arrectae) punctata (Taylor) Taylor has been treated as an endemic of Atlantic Europe. Studies of larger specimen sets demonstrated that the species is widespread in mountainous regions of the Neotropics where it is known under several names including P. stolonifera Lindenb. & Gottsche, P. choachina Gottsche and P. patzschkei Steph. In tropical Africa P. punctata is established as Plagiochila subalpina Steph., nom. illeg. The sporophyte of P. punctata is described for the first time, based on material from Costa Rica. A maximum likelihood analysis of a nrITS sequence alignment with sequences of P. sects. Fuscoluteae (outgroup), Arrectae, and Rutilantes as well as of P. rubescens (Lehm. & Lindenb.) Lindenb. results in a tree with well bootstrap supported Arrectae and Rutilantes clades. ITS sequences of Plagiochila punctata from the Comoros and Zaire are placed in an unsupported monophyletic lineage together with P. punctata sequences from the British Isles and Ecuador. The species is nested in a robust clade with P. spinulosa (Dicks.) Dumort. and P. stricta Lindenb. The weak genetic separation of these three species indicates a recent diversification; the disjunct ranges may be the result of long range dispersal events. Plagiochila rubescens from southern South America is placed sister to P. sect. Arrectae. The latter section possibly originated from southern South American ancestors, diversified in tropical America after the uplift of the Andes and reached the Holarctics and tropical Africa by long range dispersal of diaspores.