Comparative Anatomical Analysis of the Vegetative Organs of Althaea officinalis and Malva thuringiaca (Malvaceae) Introduced in the Mangyshlak Region

This article presents the results of microscopic studies of the vegetative organs of natural species from Mangystau Region, Althaea officinalis L. and Malva thuringiaca (L.) Vis. (Malvaceae), which were introduced there under conditions of the Mangyshlak Experimental Botanical Garden (MEBG) (city of Aktau). The anatomical structures of the leaf, stem, and rhizome have been studied. Both species are characterized by a similar structure of the vegetative organs. The leaf, stem, and rhizome of A. officinalis are larger than the respective microstructures of M. thuringiaca, which can be explained by differences in the species ecology. The following diagnostic features have been proposed: arrangement of trichomes, mesophyll thickness, and placement of druses for the leaves; thickness of the cortical parenchyma and shape of the sclerenchyma areas for the stem; and thickness of the cortical parenchyma and presence of one- or two-row core rays for the rhizome. Species differences have been established in the number of layers of the palisade leaf tissue; the size and arrangement of star-shaped trichomes and the shape and arrangement of calcium oxalate druses; and the ratio of the spongy and palisade mesophyll. Differences in the structure of the transverse sections of the stem have been revealed in the thickness of the cortical parenchyma and shape of the sclerenchyma areas.