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Pollen morphology of 34 herbarium specimens belonging to 17 taxa of the genus Valeriana was studied using light and scanning electron microscopy. The aim of this research was to evaluate the taxonomical value of palynomorphological data for species-specific identification. Pollen grains are monads, radially symmetrical, isopolar, tricolpate, oblate to prolate (P/E = 0.69–1.59); medium- or large-sized (P = 26.60–66.50 µm; E = 23.94–57.19 µm). Colpi are long, medium-length or short, with acute, obtuse or rounded ends. Four types and eight subtypes of exine sculpture were recognised: type I—echinate-verrucate (5 spp.), type II—echinate-nanoechinate-verrucate (10), type III—echinate-microechinate-nanoechinate-verrucate (1), type IV—echinate-microechinate-nanoechinate (1). Additional characters of taxa of Valeriana diagnostic at species level for the purposes of taxonomy are: size of pollen and colpi, exine sculpture: presence/absence of verrucae, their form, size and form of echini/microechini/nanoechini, their number, pattern of tectum in areas between echini, exine thickness in mesocolpia and apocolpia. Our palynomorphological data support the results of molecular phylogenetic studies. The close phylogenetic relationships of the species V. montana, V. tripteris, V. supina and V. pyrenaica are also supported by their palynomorphological characters, such as exine sculpture (type I). Cluster analysis mainly supports the definition of pollen types and subtypes (based on qualitative data), since species are grouped as five separate branches. The pollen grains of five taxa were analysed for the first time in the current study.

Comparative palynological studies of Dipsacaceae s.str. show considerable diversity in the pollen grain morphology of its representatives. The aim of this research was to provide more detailed palynomorphological data on selected taxa whose pollen grains are characterised by tricolpate apertures (Pterocephalus plumosus, Succisa pratensis and Succisella inflexa). The pollen morphology of P. plumosus was studied using both light microscopy and scanning electron microscopy. The pollen grains are tricolpate, suboblate to prolate; large in size. Their outline in polar view (amb) is subcircular, rarely trilobate. The brevicolpi have a distinct margo and acute ends. The exine sculpture is echinate-microechinate-nanoechinate. The exine structure (columellae) of the pollen grains of P. plumosus, S. pratensis and S. inflexa was analysed for the first time in the current study. Pollen grains in P. plumosus are distinguished by long and dense columellae in the mesocolpia, and longer in the apocolpia. Our new ?alynomorphological data support a close relationship between S. pratensis and S. inflexa by the presence of shorter sparse columellae throughout the pollen exine. The UPGMA dendrogram shows the distinctive morphometric characters of P. plumosus pollen grains, which is thus included as a separate branch.

Pollen morphology of herbarium specimens of four Centranthus species (C. ruber, C. longiflorus, C. kellereri and C. calcitrapae) was studied using LM and SEM. The research aim was to provide data on their pollen characteristics and to evaluate the taxonomic value of these data for species-specific identification. Pollen grains are tricolpate, suboblate to prolate (P/E = 0.81–1.42); medium- or large-sized (P = 49.21–90.44 μm; E = 43.89–93.10 μm). Colpi are long or medium-length, wide at equator, tapered to acute or obtuse ends. Exine sculpture is echinate-microechinate-nanoechinate; echini (1.00–1.39 μm high) and microechini (0.55–0.98 μm) are conical, with straight or convex sides and acute apices, nanoechini are 0.22–0.46 μm high. Most important characters of taxa diagnostic at species level for the taxonomy are: size of pollen and colpi, exine structure, size of echini and microechini, and pattern of tectum in areas between echini. Pollen grains of C. calcitrapae and C. macrosiphon (sect. Calcitrapa) are generally smaller in size than grains of C. ruber, C. longiflorus and C. kellereri (sect. Centranthus). Pollen of C. kellereri was analysed for the first time in the current study.