Tamarix laxa (Tamaricaceae), a new species in the flora of Ukraine

Abstract

Tamarix laxa, a new species for the flora of Ukraine, is first reported for the Bilosaraiska Spit on the northern coast of the Sea of Azov in the Meotyda National Nature Park, Donetsk Region, Ukraine. Its main range extends from the eastern coast of the Sea of Azov to China. Thus, the new location is the extreme northwestern point of the species' natural distribution range. The presence of representatives of the genus Tamarix at the Bilosaraiska Spit has been known for more than 100 years, but T. laxa probably appeared here only in the early 1990s. In ecological and phytosociological terms, the species is confined mainly to the shores of shallow brackish and periodically drying water bodies (bakai) and occupies the same eco­logical niche as T. gracilis; the latter has long been known in the Bilosaraiska Spit and is listed in the Red Data Book of Ukraine. Represen­tatives of the genus Tamarix are reliably identified only during the flowering period, so the growth of related species together makes it difficult to identify them during other periods. The diagnostic characters used for identification of the species of the genus growing in the Bilosaraiska Spit are discussed. It is suggested that the range of T. laxa has been gradually expanding westward during recent decades.