Persicaria robustior (Small) Bickn.
Habitat: Wet soil and shallow water on the coastal plain or near the coast; margins of ponds or quiet streams.
Range: Nova Scotia to Florida, and Tropical America.
Phenology: Flowers late July to early November.
Synonyms: Persicaria punctata (Ell.) Small var. robustior Small; Polygonum punctatum Ell. var. majus (Meisn.) Fassett; Polygonum punctatum Ell. var. robustius Small; Polygonum robustius (Small) Fern.
Known Distribution in Maine: This rare plant has been documented from a total of 1 town(s) in the following county(ies): York. The species is believed to be extirpated from Maine.