Figure 1.

(a) Geographic locations of diploid and tetraploid T. natans as well as T. incisa sampled in this study; the enlarged photograph on the right shows fruit remains of water caltrop that preserved in storage pits at the Tianluoshan site (7000–5800 yr BP), an important settlement of the Neolithic Culture (Guo et al., 2017). (b) Differences in fruit morphology between diploid cultivated and wild Trapa natans (2x, AA), tetraploid T. natans (4x, AABB) and diploid T. incisa (2x, BB). (c) Morphological differences in the root system between wild and cultivated T. natans (2x, AA). (d) Boxplots showing differences in the length and width of leaves, the length and height of fruits as well as the diameters of flowers and stems between diploid (cultivated, wild) and tetraploid T. natans and T. incisa.