Figure 1. Box-and-whisker plots showing the holoploid genome sizes (2C-values) for 9 Callitriche species and two hybrids: C. cophocarpa × C. platycarpa (C. ×vigens) and a hybrid (probably C. hamulata × unreduced gamete of C. cophocarpa) from the Tichá Orlice River, Czech Republic (Orlice).

Taxa with different chromosome numbers are separated by vertical lines. For C. obtusangula, values for samples from Italian (IT) and north-western Europe were plotted separately, due to significantly different genome sizes.