Androsace is a genus widely distributed across temperate regions of the Northern Hemisphere, with notable diversity in the Alps and the Hengduan–Himalaya regions. Although previous phylogenetic studies have advanced understanding of the evolutionary history of Androsace, its biogeographic origins and diversification history have remained unresolved due to limited species sampling and low statistical support.

In a study published in Journal of Systematics and Evolution, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences provided the clearest family tree yet for this group and confirmed that several formerly recognized genera including Douglasia, Vitaliana, and Pomatosace are actually part of Androsace, and should be treated as one broader group.

The researchers sequenced the complete chloroplast genomes and nuclear DNA of over 100 species of Androsace and its close relatives. Their results showed that these flowers first appeared on the ancient Tibetan Plateau about 33 million years ago, and from there they spread to Europe, North America, and beyond.

Using fossils and molecular clocks, the researchers calculated that the common ancestor of all living Androsace lived in the Pan-Tibetan Highlands (today’s Qinghai-Tibet Plateau, Himalayas, and Hengduan Mountains) during the early Oligocene, a time when the climate was cooling and alpine habitats were forming. Over millions of years, the plant migrated westward across Eurasia and repeatedly crossed the Bering Strait into North America. The Tibetan region remained the main source of these dispersals, sending out at least a dozen separate waves of colonisation to East Asia alone.

The phylogenetic tree robustly divides Androsace into four well-supported clades. These clades correspond to distinct ecological niches and morphological traits: Asian alpine perennials and cushions (Clade I), Asian forestdwelling species with petiolate leaves (Clade II), the European-North American alpine and steppe lineage (Clade III), and a small Chinese endemic group (Clade IV). Crucially, the formerly recognized genera are all nested within Androsace, supporting a broader, unified circumscription.

Geological events (e.g., uplift of the Qinghai-Tibet Plateau), environmental changes (e.g., glacial-interglacial cycles), and morphological innovations jointly promoted differential radiation across clades. Notably, the diversification rate of Clade III increased significantly about four million years ago, closely associated with the origin of cushion morphology.

“Our results show that mountain biodiversity is not a product of a single historical process, but of region-specific interactions between geology, climate, and organismal innovation. Understanding these asynchronous histories is crucial for predicting how alpine ecosystems might respond to ongoing global change,” said XING Yaowu of XTBG.

Species richness, sample distribution, and representative species of  Androsace (Image by XTBG)

First published: 13 August 2026