Proserpinaca pectinata

Proserpinaca pectinata is a little-known species closely related to P. palustris that lives in North America, from eastern Canada (Newfoundland and Nova Scotia) over the eastern and southeastern USA down to Florida and Texas. It is on sale by aquatic plant nurseries in the USA, however, it is probably not available in Europe yet.

P. pectinata mainly differs from P. palustris by its leaves whose emersed as well as submersed form is characterised by fine pinna, which you otherwise find in milfoil species (Myriophyllum). The emersed leaves of Proserpinaca palustris, however, are usually unparted with a serrate margin.
The species of the genus Proserpinaca differ from most Myriophyllums by its leaves that don't grow in whorls but alternating on the stem.

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