Populations of obligate petrophytes of the Mountain Crimea Heracleum ligusticifolium M. Bieb. (Apiaceae) and Silene jailensis N.I. Rubtzov (Caryophyllaceae) are distinguished by their small number due to the internal mechanism of their self-regulation: in small-area local stony habitats, plants of pregenerative age are regularly eliminated. This mechanis m operates independently of external threats, the adverse effect of which was smoothed out by the structural features of populations: the predominance of long -lived generative plants in S. jailensis, and the abundance of viable seeds in H. ligusticifolium. However, in recent years, the population of the Nikitskaya Yayla has been observed to have a weak lack of seed renewal of Silene jailensis and a complete lack of seed renewal of Heracleum ligusticifolium. This circumstance led to intra-population destructive processes. The probability of degradation and extinction of populations actualized the development of methods of reproduction and maintenance of plants of these species in vitro. By now, there is a stock of plants of these species that can be used for in situ reintroduction.