Ontogenetic structure of Thymus L. (Lamiaceae) coenopopulations in Yakutia

Abstract

Ontogenetic structure of coenopopulations of four model species Thymus extremus, T. indigirkensis, T. brevipetiolatus and T. pavlovii widely distributed in Yakutia was studied. It was established that species coenopopulations were normal, most of them incomplete. Dependence of the type of the ontogenetic spectrum of coenopopulations on growth conditions and ontogenesis pattern was revealed in thymes of different biomorphs. The bimodal type of the ontogenetic spectrum (monocentric dwarf subshrub T. extremus) is conditioned by irregular seed regeneration and lack of ripe and old generative stages. Formation of the left-side type of the ontogenetic spectrum is governed by the emergence of vegetative propagation of individuals (unobvious polycentric dwarf subshrub T. brevipetiolatus and dwarf semishrub T. indigirkensis) and substrate features (distinct polycentric dwarf semishrub T. pavlovii).