Pond populations in Cape Cod described as Persicaria puritanorum (≡ Polygonum puritanorum) have been treated by recent authors as a synonym of P. maculosa (≡ Polygonum persicaria) based on gross morphology. However, consistent differences in leaf and inflorescence features raise the question as to whether this is an extreme phenotype of P. maculosa, an ecotype of that species, or a distinct tax...