MORPHOLOGICAL CRITERIA FOR THE DIFFERENTIATION OF AGE STATUS OF PTILOSTEMON ECHINOCEPHALUS (WILLD.) GREUTER (LAMYRA ECHINOCEPHALA (WILLD.) TAMAMSCH.)

Abstract

Ptilostemon echinocephalus (Willd.) Greuter (Lamyra echinocephala (Willd.) Tamamsch.) is the only species of the genus Ptilostemon from the Asteraceae family that grows on the Crimean Peninsula. The relic area of Ptilostemon echinocephalus distributed by the Crimea, the Caucasus, Asia Minor. The species is included in the Red Book of the Republic of Crimea, Krasnodarskiy and Stavropolskiy Krays of the Russian Federation. The article is the result of a long-term study of morphological criteria of Ptilostemon echinocephalus age status. Thus, the ontogenesis of individuals of the species Ptilostemon echinocephalus includes 12 age states, the total during of ontogenesis lasts 15–18 years. The main characters of the pregenerative period differentiation of development are the number of leaves and the differentiation degree of the leaves lamina. During the study, another important feature was identified to indicate different age stages, the ratio of vegetating and dried leaves. Generative plants were subdivided into: immature generative (g1), adult (mature) generative (g2) and old generative (g3). For the generative stage of development, the ratio of generative and vegetative rosettes, the ratio of dried and vegetative shoots, and the number of baskets were indicative. Differentiation of subsenile and senile age states is conducted according to the same criteria that are used for generative individuals, the main emphasis is on the ratio of dried and vegetative parts.The article also notes the specificity of the course of ontogenesis depending on the ecological-cоenotic conditions in the petrophytic steppes and phrygana communities of the Crimea.