Nymphoides peltata/Villarsia peltata is indigenous to the Mediterranean.
For a similar European variety (they have fewer petals, but are very much the same otherwise), see Hydrocharis morsus-ranae. The American version is Limnobium.
Here's a pic of N. peltata that shows the variety with only a slight fringe: You are not allowed to view links. Register or Login to view.
I've researched it for quite some time, but haven't been able to find info on whether N. indica had reached Europe by the Middle Ages. It's an easy plant to transplant, so it's possible it was in the Middle East by then, but maybe not Europe.
For a similar European variety (they have fewer petals, but are very much the same otherwise), see Hydrocharis morsus-ranae. The American version is Limnobium.
Here's a pic of N. peltata that shows the variety with only a slight fringe: You are not allowed to view links. Register or Login to view.
I've researched it for quite some time, but haven't been able to find info on whether N. indica had reached Europe by the Middle Ages. It's an easy plant to transplant, so it's possible it was in the Middle East by then, but maybe not Europe.