Achene micromorphology and its taxonomic significance in some species in Taraxacum sect. Palustria (Asteraceae)

The genus Taraxacum is one of the largest and taxonomically most complicated apomictic genera. Currently, it is considered to consist of over 2800 species placed within 60 sections. Due to the large number of species, and their uniform morphological design and plasticity of leaves, the identification of plants at the species level is challenging even for specialists. This problem significantly hinders the study of their properties and the rational use of these valuable medicinal and nutritional plants. This paper presents the results of research on the morphology and micromorphology of achenes of 28 Taraxacum species of sect. Palustria and for comparison one species per section of: Erythrosperma, Naevosa, Piesis, and Taraxacum. The achenes were measured with a stereoscopic microscope and a biometric program, and micromorphological studies were performed by scanning electron microscopy. It has been shown that traits associated with achene morphology and micromorphology have a high diagnostic value, allowing us to distinguish sections as well as species within the sect. Palustria. Based on the examined achene features, a dichotomous key for determining the studied species was constructed.