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This study demonstrated the correlation between Thymus life-forms and conditions in the Tien Shan mountains, in which different vegetation belts can be located at different altitudes depending on a particular ridge. We selected four species of Thymus that are widespread in Tien Shan mountains (Thymus diminutus Klokov, Thymus dmitrievae Gamajun, Thymus karatavicus Dmitrieva, and Thymus seravschanicus Klokov). Eco-morphological and phytocenotic approaches were used to study the life-forms and biomorphs within the genus Thymus in this region. The module structure and sympodial axis were analyzed according to the slope steepness and stone and (or) herbaceous covering. Acrotonic and basitonic module branching types are characteristics of dwarf shrub and dwarf subshrub life-forms, respectively. The dwarf shrub develops in open spaces in the steppe and forest, and the dwarf subshrub develops in different vegetation belts from steppe to alpine. Thymus dwarf shrub and dwarf subshrub life-forms were characterized by an implicitly polycentric biomorph type (mature plant comprising several closely located growth centers). Thymus species in the Tien Shan mountains exhibited morphological variability. We propose that the branching of Thymus plants can be used as an indicator of a specific vegetation belt in the Tien Shan mountains, and can be used to predict the behavior of other species with similar morphology.

Biomorphological features of the steppe dwarf subshrub Scutellaria przewalskii were revealed. In most of the range, in petrophytic variants of temperate steppes, this species develops as a monocentric dwarf subshrub with anisotropic generative shoots. The morphogenesis of S. przewalskii individuals under the conditions of temperate steppes (Aridity index (I) = 17) is described in detail. A comparative analysis was performed on morphological functions of five steppe dwarf subshrubs from the genus Scutellaria (S. przewalskii, S. supina, S. grandiflora, S. tuvensis, S. sieversii) was carried out by 14 qualitative and quantitative indicators. As a result of a comparative analysis of individuals growing in different types of steppe communities: meadow steppes (I = 55), temperate steppes (I = 15–17), desert steppes (I = 9), common features of the development of individuals of dwarf subshrub were revealed: the basisympodial growth of the shoot system; the lignification of the shoots’ basal parts; the renewal buds location above the substrate surface; short monopodial growth of the primary shoot, the presence of the main root during the entire ontogenesis. Differences between dwarf subshrub are associated with the structural features of shoots and the skeletal axes, their age, the pregenerative period duration decrease.

Morphological structure and polyvariation of development of Thymus karatavicus, an endemic of the West Tien Shan, were studied. Species habitats are monotypic, restricted to Festuca ovina communities of the Syrdarya Karatau and Talass Аlatau. T. karatavicus was established to be an implicitly polycentric dwarf shrub. An adult plant represents a clump consisting of primary and partial bushes. In morphogenesis, seed individuals pass phases of a primary shoot, a primary bush, and a clump sequentially and vegetative individuals pass phases of a partial bush and a system of partial bushes. The individual ontogenesis does not exceed 20 years; over this period, individuals pass 7 ontogenetic states sequentially. Self-preservation of populations is performed by seeds and vegetatively; under changes of growth conditions, the individuals exhibit polyvariation of development. A specific pattern of the morphological structure and development of T. karatavicus determines preservation and sustainable status of its populations in the West Tien Shan Keywords: Endemic plant, Dwarf shrub, Morphogenesis, Plant architecture, Tien Shan

The structure of 24 species of Thymus and 12 species of Scutellaria was studied using the architectural approach. For the first time, an architectural unit was described, it is a branched sympodial axis. The architectural unit consists of sympodial axes n+1 order, formation shoots, branching shoots, ephemerous shoots. The wide distribution of species and development of species in contrasting habitat conditions is due to the diversity of sympodial axes and shoots that are part of the architectural unit. Depending on the type of branching and the spatial position of sympodial axes, six modifications of architectural unit were identified. It is established that the structure of mature individuals are formed due to the repetition one of the same modification of architectural unit or a combination different modifications of architectural unit. Each of the variants of the combination determines the type of life form (dwarf shrub or dwarf subshrub) and biomorph (monocentric, dense polycentric, sparse polycentric) and depends on the conditions of the ecotope. The identified modifications of the architectural unit and the variants of their combination determine the strategy for the development of dwarf shrubs and dwarf subshrubs in the development of Northern and Central Asia.

The results are obtained which expand understanding of the semi-woody plant structure. Ontomorphogenesis and life form of Ziziphora interrupta Juz., growing in Tajikistan, were studied. It was established that the ontogenesis of individuals is simple, incomplete, its duration is at least 14-16 years. The multivariance of ontogenesis is revealed, expressed in the rates of development and omissions of ontogenetic states. The description of the formation shoot showed that the individual is characterized by a basisympodial growth and the formation of the life form of a dwarf subshrub.

The work was carried out on the grounds of the Kuzbass Botanical Garden. The study material is a perennial, rod-rooted herbaceous plant known as Althaea officinalis L. Included in the Red Book of the Kemerovo Region with status 2 - declining. It has been found that during the first year of life, individuals go through 5 ontogenetic stages: seedling, juvenile, immature, virginile and young generative. The latent, pre-generative and generative periods of A. officinalis are characterised in detail. The forming of the caudex and the growth of the primary semi-rosette monocarpic shoot is described.

The structure of five Ziziphora interrupta coenopopulations in Tajikistan was described in the article. It was found that most coenopopulations are stable, have a centered ontogenetic spectrum with a maximum on mature generative individuals. This is due to the slow rates rates of plant development in the middle and fast at the beginning and end of ontogenesis. The deviation from the typical centered spectrum is associated with the irregularity of seed renewal and the polyvariant ontogeny of individuals growing on mobile substrates and steepness of slopes. The right-sided spectrum is formed as a result of anthropogenic impact (collection of medicinal raw materials), what leads to a gradual aging of the coenopopulation and its loss from the community.

The article deals with the seasonal rhythm of development of the bulbaceous acrosympodially accreting polycarpic Allium trautvetterianum Regel (the subgenus Melanocrommyum) when growing in the Kulyab Botanical Garden of the Khatlon Scientific Center, Academy of Sciences of Tajikistan in 2010-2015. Duration of vegetation and phenological phases is described. The species is characterized on the phenorhytmotype as a shortgrowing ephemeroid. Influence of weather conditions on duration of phenological pahses is shown. It is established that the rhythm of development completely corresponds to the eastern variant of Mediterranean climate.

Seed productivity of 4 Ziziphora species: Z. pamiroalaica, Z. interrupta, Z. brevicalyx, and Z. suffruticosa growing in the Pamir-Alay Mountains was stUdied. It was revealed that the indicator of real seed productivity did not exceed 40 %. Seed viability and character of germination were studied. It was established that seeds of all species did not have a dormancy period, had high viability, up to 95 % and high germination energy.