This article studies the morphological parameters of vegetative and generative organs of different age groups of Crataegus ambigua from four populations in Western Karatau (Mangistau region, Kazakhstan). The study examined four populations Pop 1 Sultan Epe, Pop 2 Karakozaiym, Pop 3 Emdikorgan, and Pop 4 Samal located in various gorges of western Karatau. Some phylogenetic inference methods were applied using six genetic markers atpF-atpH, ITS, matK, psbK-psbI, rbcL, and trnH-psbA. We also used a statistical analysis of the vegetative and generative organs of plants for three age groups of plants (virgin, young generative, and adult generative). According to the age structure, Samal populations have a high concentration of young generative plants - 42.3% and adult generative plants - 30.9%. Morphological analysis showed the significance of the parameters of the generative organs and separated the Samal population into a separate group according to the main PCoA coordinates. The results of the floristic analysis showed that the populations in the Samal have a high concentration of species diversity. The comparative dendrogram of UPGMA shows the informativeness of the use of genetic markers and the psbK-psbI region can be used to judge the difference between the fourth Samal population and the other three.

The morphologically variable moss Trichostomum brachydontium is very common in south and west Europe, particularly under Mediterranean and Atlantic climates. A morphological study was conducted alongside a molecular phylogenetic study based on nr ITS and cp rbcL regions in order to assess if T. brachydontium is an exceptionally polymorphic species as evidenced by the number of described infraspecific taxa from the last century or, alternatively, if it includes more than one species, and if so, to find the valid name for them. Phylogenetic analyses of both nuclear and chloroplast datasets show that there are four well-supported clades. While the ITS based tree is in good agreement with the morphological data, there are a few inconsistencies with reference to the rbcL tree; this may be explained by incomplete lineage sorting or by hybridization. The morphological survey revealed well-defined discriminate differences between the four phylogenetic lineages. The taxonomic conclusions include the recognition of four species: T. brachydontium s.s., T. herzogii (a new name proposed for var. cuspidatum), T. littorale and T. meridionale (a new name proposed for var. densum). Lectotypes are designated for T. brachydontium and T. littorale. Our results underline the ongoing need of integrative studies to examine further the underestimated diversity of the T. brachydontium complex in other regions.