Аңдатпа
The article presents the results of study of the ontogenetic state, the number and age range coenopopulations of the rare species Anthemis trotzkiana Claus in the conditions of Aktobe region. During thestudy of the ontogenesis of Anthemis trotzkiana Claus 3 periods and 6 ontogenetic stateswere identified. The main coenopopulation indicators are calculated and the ontogenetic structure of this speciesischaracterized.According to the age index (Δ) and energy efficiency index (ω) in 3 cenopopulations in the 1st population, the number is approximately 0.40-0.44, the energy efficiency index ranges from 0.51 to 0.74, 1CPΔ = 0.40, ω = 0.68, 2 CPΔ = 0.44, ω= 0.51 and 3 CP Δ = 0.42, ω = 0.74. In the 2nd population,the Anthemis trotzkiana indicators at 4, 5 and 6 coenopopulations are relatively high. 4 CP Δ = 0.43,ω = 0.76, 5 CP Δ = 0.44, ω = 0.74 and 6 CP Δ = 0.44, ω = 0.75, and in 3 populations 6, 7 and 8 CPthe age index is higher 0.54–0.63 compared with the other two populations, and the efficiency indexof the 7th coenopopulation is rather low ω –0.48, 7 CP Δ = 0.56, ω = 0.48, 8 CP Δ = 0.54, ω = 0.70and 9 CP Δ = 0.63, ω = 0.68.Under the conditions of the Aktobe region, during the study of the rare species Anthemis trotzkianaClaus the age index (∆) and energy efficiency index (ω), i.e. the delta omega values, as well as the recovery, replacement and aging indexhave been described.Key words: ontogenetic condition, age structure, coenopopulation, Anthemis trotzkiana Claus.