Two new sage species discovered in China's Hengduan Mountains

Researchers have identified two new sage species in China's Hengduan Mountains, bringing the country's total number of native species in the genus to 94, according to Shanghai Chenshan Botanical Garden.

The Hengduan Mountains stretch across parts of Sichuan and Yunnan provinces and the Xizang Autonomous Region in southwest China, along the southeastern edge of the Qinghai-Xizang Plateau.

The two species, Salvia zayuensis and Salvia toxantha, belong to the genus Salvia, one of the largest in the mint family, with around 1,000 species worldwide. Many are valued for their medicinal, ornamental and culinary uses, or for essential oil production.

Familiar members include danshen, used in traditional Chinese medicine; chia, known for its edible seeds; clary sage, used to produce essential oils; and scarlet sage, widely planted in urban flower beds.

Both new species were found in the Hengduan Mountains, a region rich in plant diversity and a key center of sage diversity in China, said Huang Yanbo, an engineer at the botanical garden. The region is a major focus of the team's field surveys.

In April 2019, researchers from the garden found an unidentified sage during a field expedition in Zayu County in southwest China's Xizang Autonomous Region, at the western end of the Hengduan Mountains.

The plant resembled Salvia cyclostegia but had larger leaves. Its young stems and the undersides of its leaves and bracts – modified leaves surrounding the flowers – were densely covered in grayish-white, woolly hairs. At an early stage, its flower cluster was wrapped in layers of broad, egg-shaped bracts, giving it the appearance of an elongated peach.

In August 2023, the team collected another suspected new species in Songpan County in southwest China's Sichuan Province, in the northern Hengduan Mountains.

It resembled Salvia smithii but lacked that species' lemon scent. Its flowers curved like a bow, and its stamens – the male reproductive parts – were shorter.

Further research combined observations of the plants' physical features with molecular evidence. This included an evolutionary family tree based on chloroplast DNA, which helped establish their relationships with other sage species.

The researchers confirmed that both plants were new species, naming the one from Zayu Salvia zayuensis and the one from Songpan Salvia toxantha. The findings were recently published in the international journal PhytoKeys.

Shanghai Chenshan Botanical Garden has long worked on the conservation and use of sage species from around the world. It now maintains 78 species native to China outside their natural habitats and houses a national repository of genetic resources for mint-family plants.