Biosystematic studies on the family tofieldiaceae III. classification of tofieldia nuda into three species and three varieties

In order to reexamine the taxonomic coherence of Tofieldia nuda, which shows wide morphological variation within the species, we analysed sequences of plastid trnK, trnL, and trnL-F and nuclear ITS of T. nuda and seven further species of Tofieldia. We found that T. nuda contains three different lineages supported with 99% or 100% bootstrap value: one lineage sister to T. coccinea (100%), one linage sister to the Chinese species T. divergens and T. thibetica (98%-100%), and a third lineage sister to the second lineage plus T. divergens and T. thibetica (99%-100%). As the wide morphological gaps among T. nuda, T. coccinea, T. divergens, and T. thibetica prevent us from considering them as conspecific with one another, the three lineages of T. nuda are regarded as different at the species level. The first lineage corresponds to T. nuda s.str., the second to T. furusei (formerly T. nuda var. furusei), and the third to T. yoshiiana, often considered a synonym of T. nuda. Tofieldia yoshiiana is further divided into three varieties, var. yoshiiana, var. kanwonensis comb. nov. and var. hyugaensis var. nov. A key to the three species and varieties is provided.