a water milfoil, Myriophyllum aquaticum.
a North American featherfoil, Hottonia inflata.
10 Commonly Misused WordsSome words have taken on incorrect meanings over time through consistent misuse. Make sure you're using the right word.
Origin of water feather
An Americanism dating back to 1810–20
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019