the details of leaf shape. Leaves near the top of branches may merge into bracts. The foliage is aromatic, especially when crushed, with a fragrance described as sage-like, a blend of sage and lavender, or like turpentine. The flowering season of S. yangii can be as long as June through October, although populations in some parts of its range, such as China, may bloom in a much more restricted period. The inflorescence is a showy panicle, , with many branches. Each of these branches is a raceme, with the individual flowers arranged in pairs called verticillasters. Each flower's calyx is purple, densely covered in white or purple hairs, and about long. The corolla is tube-shaped, formed from a four-lobed upper lip and a slightly shorter lower lip; the blue or violet blue petals are about 1 cm long. The style has been reported in both an exserted—extending beyond the flower's tube—form and one contained within the flower; all known examples of S. yangii in cultivation have exserted styles. Gardening author Neil Soderstrom describes the appearance of the flowers from a distance as "like a fine haze or fog". The fruits develop about a month after flowering, and consist of dark brown oval nutlets, about . Phytochemistry The phytochemistry of Russian sage is under basic research. Analysis of its essential oil has identified over two dozen compounds, although the compounds detected and their relative prevalence have not been consistent. Most analyses have identified various monoterpenes and monoterpenoids as the dominant components, such as carene, eucalyptol, limonene, γ-terpinene, and (+)-β-thujone, although the essential oil of a sample from the Orto Botanico dell'Università di Torino had camphor as its most prevalent component. Other monoterpenes, camphene, α-pinene, and β-pinene are also present, as are sesquiterpenes such as γ-cadinene, δ-cadinene, trans-caryophyllene, and α-humulene. Several terpenoid alcohols—borneol, cedrol, and menthol—have been extracted, as have caffeic acid and ferulic acid. More complex compounds have been isolated, some of which were first identified in this manner, including perovskatone; the glycosides atriplisides A and B; and atricins A and B, a pair of triterpenes that are similar to oleanane. Four diterpene glucosides have been isolated by extraction. Similar species Nine species are recognised within Salvia subg. Perovskia. S. abrotanoides shares much of the range of S. yangii, but is distinguished by its bipinnate leaves. Hybrids between these two species may occur naturally. Restricted to Turkestan in its native range,