I have a weed growing in my lawn that at first I identified as Water Smartweed Polygonum coccineum, but then I saw a plant with very similar appearance and characteristics identified as Water Smartweed Polygonum amphibium. The Plant Database has these as two separate entries. I am wondering if these are the same plant, or two different but very similar plants?

thank you!

Depending on who you believe, they are either (closely related) separate species or a single species. And they might belong in the Polygonum genus, or the Persicaria genus, or possibly even the Fallopia genus. The taxonomy of the whole Polygonum/Persicaria/Fallopia group is in an extreme state of flux at the moment, to say the least.

Thanks Kent.