1926-1930 botany instructor, Krupskaya Academy, of Communist Education. 1930-1931 geobotanist, Institute of Agropedology. 1931-1932 at Dept, of Territorial Organ, and Territorial Organization Research Institute, USSR Popular Commissariat of Agriculture.
1932-1938 instructor, 1938-1946 lecturer, since 1946 Professor, Moscow University. 1937-1942 Candidate of Biological Science. Took part in following expeditions: 1926-1928 to Starobelsk Steppe.
1929 to Salsk Steppe. 1930 to Orenburg Steppe. 1931 to Ishim area, Troitsa area and Northern Kazakhstan (Kusfanay and Petropavlovsk Steppe).
1932 to Troitsa and Chelyabinsk areas. 1933 to Streletsky Steppe, Kursk Oblast. 1934 to Mugodzhary; 1936-1937 to Naurzum National Park, Kustanay Oblast.
1938 to Caucasian National Park, Krasnodar Oblast. 1942 to Kopet-Dagh, Turkmenistan. 1944-1948 to Naurzum and Central Black Earth National Parks.