Morphological features of the flower of Symphoricarpos species (Caprifoliaceae) introduced to Ukraine

Abstract

With the help of light and scanning electron microscopy, the features of inflorescences and flowers of six species of the genus Symphoricarpos introduced to Ukraine were studied, and the peculiarities of their structure were specified. Morphological peculiarities of the calyx, corolla, stamens, and style, differentiating S. albus (including S. racemosus and S. rivularis), S. hesperius, S. mollis, S. occidentalis, S. orbiculatus, and S. oreophilus var. utahensis, were determined. The obtained data are important for identification of the species and taxonomy of the genus Symphoricarpos. In particular, the results of our study showed that flowers of S. racemosus, S. rivularis, and S. albus share common features and this supports their synonymy under the name S. albus. Other five Symphoricarpos species showed differences in their floral morphology.Among the important features for identification of Symphoricarpos species introduced to Ukraine, which were not mentioned in available literature sources we can list: the number of flowers in the inflorescence, features of pedicels, shape and features of bracts pubescence, shape of calyx teeth and their pubescence, presence or absence of corolla tube convexity, presence of ovoid projection of anther’s connective, and size of all the floral elements.Symphoricarpos oreophilus var. utahensis has unique features of floral morphology. Its single flowers located in the axis of the leaves on the pendent pubescent pedicels; the calyx is elongated, fusiform; the corolla is narrowly tubular, without a convex at the base; the stamens are shorter than the corolla tubule or rarely of the same length, with a clear ovoid projection on the apex.