P. scrophularifolia is less upright; some forms have white flowers. The flowers of P. scabiosifolia are yellow. Taxonomy Salvia yangii was described, under the name Perovskia atriplicifolia, by George Bentham in 1848, based on a specimen collected by William Griffith in Afghanistan, now preserved at the Kew Gardens herbarium as the species's holotype. The specific epithet atriplicifolia means "with leaves like Atriplex", referring to its similarity to saltbush. While commonly known as Russian sage, S. yangii is not native to Russia. A population collected in Taxkorgan Tajik Autonomous County, Kashgar Prefecture, Xinjiang, China was described as a separate species in 1987 and given the name Perovskia pamirica, but was later considered synonymous with P. atriplicifolia. In 2017, P. atriplicifolia was transferred to the genus Salvia. The combinations Salvia atriplicifolia and Salvia pamirica, however, have already been preoccupied by distinct taxa, thus new specific epithet yangii, honouring Yang Changyou, one of the authors of P. pamirica, was given to the species. Phylogenetics Within the family Lamiaceae, the large genus Salvia had long been believed monophyletic, based on the structure of its stamens. Several smaller genera, including Dorystaechas, Perovskia, and Meriandra were also included in tribe Mentheae, but were thought to be more distantly related. In 2004, a molecular phylogenetics study based on two cpDNA genes (rbcL and trnL-F) demonstrated that Salvia is not monophyletic, but comprises three identifiable clades. Clade I is more closely related to Perovskia than to other members of Salvia. S. yangii has been the subject of subsequent studies seeking to clarify the relationships within Mentheae. Further research combined palynological analysis of pollen grains with rbcL sequencing to provide additional support for the relationship between Perovskia and Salvia clade I. It also distinguished between S. yangii and S. abrotanoides, while confirming their close relationship. A subsequent multigene study (four cpDNA markers and two nrDNA markers) redrew parts of the Mentheae cladogram, making Rosmarinus a sister group to Perovskia. Cultivars Several cultivars of S. yangii have been developed. They are primarily distinguished by the height of mature plants and the depth of the leaf-margin incisions. Many of these cultivars, especially those with deeply incised leaves, may actually be hybrids of S. yangii and S. abrotanoides. In that context, some may be referred to by the hybrid name Perovskia ×hybrida. The most common cultivar, 'Blue Spire', is among those suspected of being a hybrid. It was selected from German plantings