Aga Tentakulus wrote:The Villarsia / Menyanthes is out of question for me because of the place of origin and the time around 1400.
But I think you mean the European sea-can (Nymphoides peltata).
But also this one is not classical.
I think Nymphoides peltata (synonym: Villarsia nymphaeoides) is the most likely species but I prefer to say Nymphoides because you cannot tell some of the individual Nymphoides species apart without a microscope. The color can vary, the leaf shape can vary, the fringe can vary from absent to fuzzy, even on examples from the same species. The one that is native to North America looks exactly like the one that is native to India (botanists used to think it was the same species).
N. peltata is native to most of Europe (but now also grows in east Asia, North America, and Africa).
I forgot to mention, the pistil sometimes sticks up above the petals of the flower (not usually, but some variants do this—I posted examples on the other threads). And yes, it is in medieval manuscripts under the names of Nymphoides and Villarsia (same drawing, different name in different regions). I think I posted at least one example.