Morphological Features of Fruits and Seeds of Some Species of the Genus Crataegus L. of the Flora of Ukraine

The genus Crataegus L. is one of the largest species in the family Rosaceae Juss. The fruits are used as medicinal raw materials (Crataegus fructus), as they contain a set of biologically active compounds. The genus is voluminous and taxonomically problematic due to significant variability, hybridization, apomixis, and polyploidy. As a result, it is difficult to determine the species of the genus. Species of the genus have a number of diagnostic features, one of which is a distinct fruit with seeds. The aim of our study was to identify and compare the diagnostic features of the fruits of seven species of the genus Crataegus flora of Ukraine, which are most often used as medicinal raw materials and are the most common in Ukraine - Crataegus laevigata, C. monogyna, C. pentagyna, C. pseudokyrtostyla, C. sanguinea, C. fallacina, and C. rhipidophylla. The study was performed using scanning and digital microscopy, and descriptions were made by standard methods. As a result, we identified features that clearly distinguished the studied species from each other. We identified mature fruits that contain only one pyrene (C. monogyna, C. pseudokyrtostyla, C. fallacina, and C. rhipidophylla), and several pyrenes (C. laevigata, C. pentagyna, and C. sanguinea) among the studied species of the genus. The studied species are characterized by spherical and ellipsoidal fruits. The predominant color is fulvous/brown with different shades, but almost-black fruits of the species C. pentagyna are well distinguished. Fruits of all studied species of the genus are fleshy, except C. sanguinea, which is floury. The species is characterized mainly by yellow flesh fruits, except C. pentagyna, which has ribbed fruits. The fruits of C. monogyna plants differ from those of other studied species by the spinous-tuberous surface relief. Pyrenes of triangular shape are observed only in C. pentagyna. We suggest that these features can be used as additional diagnostic tools to determine the species of the genus Crataegus flora in Ukraine.