Genome size and ploidy of the German species of Veronica L. (Plantaginaceae)

Chromosome numbers and genome size estimates provide essential information for the differentiation of plant species. Especially, closely related species that are morphologically difficult to distinguish are often easily distinguishable by genome size. Flow cytometry has facilitated in recent years the detection of such differentiation at the genomic level. It further helped understand the distribution of ploidy levels within species. The genus Veronica includes 37 species in Germany including some taxonomically challenging species groups and some species with intraspecific variation in ploidy. We, here, present 36 new genome size estimates and 44 estimates of ploidy, six and seven, respectively, from Germany, for these 37 species. Estimates of V. aphylla, V. alpina, V. fruticans, and V. fruticulosa are first estimates for the species. These estimates provide an important basis for future studies on the genus. Some examples are discussed in more details, such as the distribution of ploidy levels in V. longifolia and V. chamaedrys in Germany or the importance to study ploidy levels in V. satureiifolia and relatives in southwestern Germany. ### Competing Interest Statement The authors have declared no competing interest.