Polygonum tenue Michx.
Habitat: Dry, open, acidic soil.
Range: Southern Maine to southern Minnesota, south to Georgia and Texas.
Aids to Identification: Members of the Polygonaceae are recognized by their tubular, sheathing stipules associated with the leaf blades. Polygonum, the knotweeds, are annual plants with 5 petaloid tepals. P. tenue differs from P. douglassii in that the pecicels are straight versus recurved, the leaf blades have two longitudinal folds and are minutely serrate (verus without folds and entire). Also, the flowers and fruits on P. douglasii are soon nodding, while those of P. tenue are erect or ascending.
Phenology: Flowers late June to October.
Synonyms: Polygonum tenue var. protrusum Fern.
Known Distribution in Maine: This rare plant has been documented from a total of 2 town(s) in the following county(ies): Cumberland, York.