Rustamov Eldar A. ТуркменистанAshkhabadNational Institute of Deserts, Flora and Fauna of the Ministry of Nature Protection of Turkmenistan, 15 Bitarap Turkmenistan St., Ashkhabad 44000, Turkmenistan elldaru@mail.ru Author's articles In commemoration of Sakhat M. Shammakov (1933 – 2021)