BIOLOGICAL ASPECTS OF THREATENED PSEPHELLUS ERIVANENSIS (ASTERACEAE) IN THE CONTEXT OF EX-SITU CONSERVATION

Psephellus erivanensis Lipsky (Asteraceae) is a threatened knapweed species of the Armenian flora, endemic to the Atropatene floristic sub-province of the Armeno-Iranian floristic province. According to the results of the conducted study, P. erivanensis is identified as a polycarpic rhizomatous hemicryptophyte with perennial rosettes and annual leafy elongated generative shoots. The diploid cytotype has been found for the species to be 2n=32, the karyotype is symmetric, consisting of 2 pairs of submetacentric and 14 pairs of metacentric chromosomes, 0.77-1.54 µm in size. The average pollen fertility of P. erivanensis is quite high and is in the range of 93-99%, which indicates a high seed set, contributing to the species reproduction. Plants introduced in the Yerevan Botanical Garden have a full development cycle, mature seed formation, and vegetative self-renewal ability, in comparison with natural ones, are distinguished by higher total humidity, intensity of transpiration and photosynthesis, and a decrease in water deficit. The species is recommended for ex-situ conservation through living plant collection creation and, considering its ornamental value, for utilization in arid landscaping schemes. The article is illustrated with a map of the species distribution in Armenia, original photographs, and tables.