In the Flora of China account (Pan et al. 2001) of Saxifraga mengtzeana
Engl. & Irmsch., eight synonyms were attributed to it and one variant,
recognised as S. epiphylla Gornall & Ohba, was split from it. This
study re-evaluates the taxonomic status of some of the synonyms and of
the segregated species in the light of new evidence presented here.
Morphological and molecular evidence demonstrate that populations from
north-western Yunnan and Sichuan are genetically differentiated from
those in south-eastern Yunnan and neighbouring Guangxi. Observations in
the field and in cultivation show that the peltate petiole attachment
diagnostic of S. mengtzeana var. peltifolia Engl. & Irmsch. is
developmentally labile. Similar observations combined with molecular
data show that viviparous phenotypes, formerly treated as S. epiphylla,
although largely under genetic control, occur sporadically throughout
the ranges of both northern and southern taxa. Populations from
north-western Yunnan and Sichuan are best recognised as S. geifolia
Balf.f., whereas those from south-eastern Yunnan and neighbouring
Guangxi are S. mengtzeana. Peltate-leaved variants of the latter are
given no status and are relegated to complete synonymy. Viviparous
phenotypes of S. mengtzeana are demoted to the rank of forma, as f.
epiphylla; analogous phenotypes of S. geifolia are newly described as f.
vivipara. Keywords China, Saxifragaceae, Phylogeny, Morphology, Taxonomy