Fallopia scandens (Linnaeus) Holub. Section: Fallopia. Phen: Jul-Oct. Hab: Moist to wet open habitats. Dist: NS, ON and MB, south to c. peninsular FL and se. TX.
Origin/Endemic status: Native
Taxonomy Comments: There has been widespread skepticism about the recognition of two taxa at species or variety rank, 'scandens' and 'cristata'. Desjardins et al. (2023) cast additional doubt based on molecular evidence ("almost identical for the markers analysed", "not worthy of taxonomic recognition" based on molecular, morphometric, and chemotaxonomic evidence. We here lump the two taxa sometimes recognized. If recognized, Fallopia cristata has smaller floral parts: perianth 7-10 mm long at maturity (measured from the pedicel joint to the tip) and achenes 2-3.5 mm long, vs. perianth 10-15 mm long at maturity (measured from the pedicel joint to the tip) and achenes 3.5-6 mm long
Synonymy: = Ar, FNA5, K3, K4, Mi, Pa, Tn, Desjardins et al (2023), Ronse De Craene & Akeroyd (1988); = Polygonum scandens L. – Tx, W, WH3, WV, Horton (1972); = Tiniaria scandens (L.) Small; > Bilderdykia cristata (Engelm. & A.Gray) Greene – S; > Bilderdykia scandens (L.) Greene – S; > Fallopia cristata (Engelm. & A.Gray) Holub – Il, NE, NY, Va; > Fallopia scandens (L.) Holub – Il, NE, NY, Va; > Polygonum cristatum Engelm. & A.Gray – F, Tx, WV; > Polygonum scandens L. – F; > Polygonum scandens L. var. cristatum (Engelm. & A.Gray) Gleason – C, GW2, K1, NcTx, NcTx, RAB, Mitchell & Dean (1978); > Polygonum scandens L. var. scandens – C, GrPl, GW2, K1, RAB, Mitchell & Dean (1978)