Persicaria amphibia (L.) Gray

Locations ofPersicaria amphibia (L.) Gray in Virginia

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Botanical Name
Persicaria amphibia (L.) Gray
Common Name
Water Smartweed
Persicaria amphibia var. emersa (Michx.) J.C. Hickm.; Persicaria amphibia var. stipulacea (N. Colem.) H. Hara; Polygonum amphibium L.
Flora of Virginia Name/Status
Persicaria amphibia (L.) S.F. Gray
In their pure form, two varieties may be recognized, with a broad range of intermediates. Experimental studies by R.S. Mitchell (former curator at VPI), show that no single character will identify varieties, hence, "a key is impractical" and they are not formally recognized or mapped here. Nevertheless, they can be quite distinctive in the field. Var. emersa (Michx.) J.C. Hickman is typically strongly erect or emergent, without floating shoots and leaves; its inflorescences are 4-15 cm, its peduncles glandular pubescent, and its stipules not flanged with a collar. Var. stipulacea (N. Coleman) H. Hara often flowers in the water with inflorescences 4 cm or less; its aquatic forms glabrous, land forms sprawling and quite pubescent, stipules of all forms flanged.
Calcareous marshes, wet meadows, depression ponds, floodplain pools and ponds; also on flood-scoured rocky, gravelly, and sandy bars and shores. Infrequent in the mountains and n. and c. Piedmont; rare in freshwater tidal marshes of the inner Coastal Plain.
Native Status

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