Introduction
Saxifraga L., the largest genus of Saxifragaceae, encompasses
450–500 species that are widely distributed throughout arctic and
montane regions of the Northern Hemisphere (Ebersbach et al. 2017, Tkach
et al. 2015, Pan, Gornall and Ohba 2001). Recent molecular phylogenetic
research is monophyletic with 13 sections and 9 subsections been
recognised, providing that S. sect. Micranthes (Haw.) D.
Don is excluded(Tkach et al. 2015, Deng et al. 2015). Saxifragasect. Irregulares Haw. is the earliest lineage of Saxifraga to
diverge, which is characterized by asymmetric flowers with two unequally
elongated and three short petals (Magota et al. 2021, Tkach et al. 2015,
Zhang et al. 2020, Soltis Douglas E 2001). Section Irregularescurrently comprises 21 species, including eight recently described
species from China (Wang Fa-Guo 2008, Zhang et al. 2021, Zhang et al.
2019, Zhang et al. 2018, Zhang et al. 2017, Zhao et al. 2019, Zhang et
al. 2022b, Chen et al. 2022). Its distribution is concentrated in
eastern Asia, and most members are confined to local areas (Magota et
al. 2021, Pan et al. 2001).
The new species described here first came to our attention in 2021 when
we examined the specimens in the herbarium of the Kunming Institute of
Botany (KUN). We recognized it immediately as a new species ofSaxifragasect. Irregulares , as it possesses asymmetric flowers with two
elongated petals, while its leaf blade abaxially with white or virescent
interveinal streaks, which cannot be found in known species of S.sect. Irregulares . In May 2022, we conducted a field expedition
for this undescribed specimen and confirmed its distinctiveness. Here we
describe and illustrate the new species and provide morphological and
molecular phylogenetic evidences to support its taxonomic status and
relationships.