The necessity of the typification of the Apocynum L. s.l. (incl. Poacynum Baill. and Trachomitum Woodson) (Apocynaceae) species is crucial for future dogbane diversity estimations. Still, the original material of many taxa of the genus Apocynum s.l. is doubtful or remains to be discovered. This study’s topic is resolving a long-term taxonomic homonymy around the widely used binomial “A. sibiricum”. The misusing of the name “A. sibiricum” became a reason for long-term misunderstanding of the meaning of the binomial Poacynum sarmatiense (Woodson) Mavrodiev, Laktionov & Yu.E.Alexeev (A. sarmatiense (Woodson) Wissjul.; T. sarmatiense Woodson) and therefore for the misestimation of the Apocynum s.l. diversity in Russian and other Eurasian floras. Resolving this issue, here, we designate the lectotype of A. sibiricum Jacq. and the name “A. sibiricum Pall.” was validated within Poacynum as P. pallasianum Mavrodiev, Sytin, Laktionov & Vasjukov nom. nov. (Apocynum sibiricum auct., non Jacq.) with the lectotype selected from the original collections of Peter Simon Pallas.

Samples of essential oil from the ground part of Stachys palustris L., which grows wild in the Astrakhan region, were obtained by hydrodistillation, and the dependence of its yield on the growing season of the plant was studied. The duration of the hydrodistillation process was set experimentally to study the dynamics of changes in the results of essential oil over time. The yield of essential oil is observed in % when converted to the weight of absolutely dry raw materials. The highest yield of essential oil was obtained from plants in the flowering phase (0.19–0.20%). Quantitative analysis of the main components of Stachys palustris L. essential oil was carried out by GC-MS method. The quantitative content of essential oil components was calculated from the areas of gas chromatographic peaks without using correction factors. It was found that the composition of the essential oil of Stachys palustris L. was very specific. 47 compounds belonging to various classes have been identified. It has been established that the composition of the essential oil of the Stachys palustris L. is very specific. 47 compounds corresponding to the class were identified. Compound classes include fatty acids and acid esters (36.23%), carbonyl compounds (14.25%) and oxygenated basic sesquiterpenes (12.90%), phenols (5.85%). Among the sesquiterpenoids, the predominant component of the essential oil is hexahydrofarnesylacetone (7.5%). The oil also contains (Z)-phytol (6.78%), thymol (4.2%), β-ionone (3.36%) and β-caryophyllene (2.87%). Nonspecific components of the essential oil of the taxon Stachys palustris growing in the Astrakhan region are coumarin (10.27%) and coumaran (0.36%).

Using the steam distillation method, essential oil samples were obtained from the ground part of Artemisia taurica Willd., which grows wild in the Astrakhan region, and the dependence of its yield on the growing season of the plant was studied. The duration of the steam distillation process was established experimentally based on the study of the dynamics of changes in the yield of essential oil over time. The yield of essential oil was determined in % in terms of the weight of air-dry raw materials. The highest yield of essential oil was obtained from plants in the flowering phase (0.57–0.59%). Quantitative analysis of the main components of Artemisia taurica essential oil was carried out by GC-MS. The quantitative content of essential oil components was calculated from the areas of gas chromatographic peaks without using correction factors. Qualitative analysis was performed by comparing linear retention indices. It has been established that the composition of the essential oil of Artemisia taurica, which grows on the territory of the natural "Bogdinsko-Baskunchaksky" reserve of the Astrakhan region, is very specific. In the essential oil, 41 compounds belonging to various classes have been identified. It includes monoterpene hydrocarbons (6.57%), monoterpenoids (65.17%), sesquiterpene hydrocarbons (4.87%), sesquiterpenoids (1.85%), as well as fatty acids and acid esters (13.93%) and carbonyl compounds (4.04%). The main components of the essential oil are camphor (24.50%), borneol (8.70%), iso-dihydrocarveol (4.11%), mertinal (3.67%), terpene-4-ol (3.35%). Unlike the taxon Artemisia taurica growing in the Crimea, the studied essential oil contains a small amount of a-thujone (1.32%).

This article presents new floristic records for vascular plant species in the Eastern Caucasus, Kazakhstan, Central Asia, and Armenia, based on field surveys conducted between 2018 and 2024 and a critical revision of herbarium specimens deposited in the collections of LE, ERE, TAD, PPIU, DAG, and MHA. In total, approximately 40 new localities are documented for 24 species, encompassing endemic, Red Data Book, and alien taxa. In Tajikistan (Eastern Gissar and Central Zeravshan subregions), five new populations of endemic species were recorded: Nepeta subhastata, N. odorifera, N. gontscharovii, Eminium alberti. In Kazakhstan (Inder Solyanokupolnyy Province [belongs to the Caspian Lowland; located within the Inder District in the north of the Atyrau Region of Kazakhstan], West Kazakhstan Region), seven species are reported as new to the regional floras, including Astragalus sareptanus, A. astrachanicus, Matthiola superba, Zygophyllum ovigerum, Rorippa wolgensis, and Jurinea persimilis; most of these findings are associated with karst landscapes that served as refugia during the Khvalynian transgression of the Caspian Sea. In the Russian Federation, Tanacetum macrophyllum and Digitalis ferruginea subsp. schischkinii are reported for the first time for Dagestan, Poacynum sareptanum – for Kalmykia (based on herbarium re-identification), and the North American invasive Grindelia squarrosa – for the Astrakhan Region, where it is actively spreading along roadsides. In Armenia, twelve new locality records are provided for eight species across several floristic regions, including the endemic Ferula dseghica (Yerevan floristic region), the relict Monotropa hypopitys (Sevan floristic region), new records of Parnassia palustris for the Zangezur floristic region, and the adventive Digitaria ciliaris for the Yerevan floristic region. The results highlight the conservation significance of karst landscapes in Kazakhstan and subalpine habitats in Tajikistan as refugia for rare endemics and underscore the active expansion of alien species along transportation corridors in the Caspian lowlands. The data contributes to updateing regional floristic checklists and Red Data Books.

It is noted that one of the collections used by Alexander von Bunge in describing the Astragalus biebersteinii Bunge (section Paracystyum Gontsch.) (Bunge, 1868, 1869) “... supra Altyagatsch. 21 VII 1855 [Seidlitz]”, differs sharply from the lectotype of this species “...circa Kurt Bulak, 1796”, but quite similar to A. massalskyi Grossh. (section Cystium Bunge), differing from the latter in leaflet shape and pods pubescens. Identical specimens have been identified in herbarium collections of LE and DAG. A new species A. cordigerus Knjaz., Laktionov et Murtaz., sp. nov. is described. An original key for the identification of A. cordigerus and some similar species of sections Cystium and Paracystium is given.