Morphological peculiarities of flowers, pollen grains and fruits of Valeriana tuberosa (Valerianaceae)

Abstract

The results of the study of flowers, pollen grains and fruits of Valeriana tuberosa (sect. Tuberosae, Valerianaceae) are presented. Materials of the National Herbarium of the M.G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine (KW) were studied. The morphological structures of flowers, pollen grains and fruits were examined using both light microscopy and scanning electron microscopy; detailed descriptions of the elements of the flower, pollen grains and fruits were made and their specific features were established. The morphological features of the inflorescence, bracteoles, and the elements of the hermaphrodite flowers have been clarified. The pollen grains of V. tuberosa are 3-colpate, suboblate to subprolate (P/E = 0.85–1.33), medium- or large-sized. Their outline in equatorial view is elliptic, rarely circular, in polar view slightly trilobate or trilobate. Exine sculpture is echinate-microechinate with verrucae. The known and new carpological features are specified. In particular, papillate growth of periclinal walls of exocarp with stroke-shaped, jet and warty cuticular formations of the surface were noted the first time; details of exocarp stomatal system were revealed; features of trichomes and their cuticular structure on fruit wall are described. The obtained data are important additional characters for identification of the species and for the issues of taxonomy and phylogeny.