Oenothera tetragona Roth. Northern Sundrops. Phen: May-Aug. Hab: Moist to wet meadows, woodlands, stream margins, river-scours, rocky shoals. Dist: NL (Newfoundland) west to MI, south to e. VA and MO.

Origin/Endemic status: Native

Taxonomy Comments: Pubescence and leaf shape vary widely in this species, approaching both O. fruticosa var. fruticosa and O. hybrida (see ID notes under both taxa); as here circumscribed O. tetragona may include multiple entities.

Synonymy: = RAB, Tat; = Kneiffia glauca (Michx.) Spach – S13; > Kneiffia latifolia Rydb. – S; > Kneiffia tetragona (Roth) Pennell – S; > Kneiffia velutina Pennell – S; < Oenothera fruticosa L. ssp. glauca (Michx.) Straley – FNA10, K1, K3, Pa, W, Straley (1977), Wagner, Hoch, & Raven (2007); < Oenothera fruticosa L. ssp. tetragona (Roth) W.L.Wagner – K4, NY, Wagner (2014); < Oenothera tetragona Roth – C, Tn, Va; > Oenothera tetragona Roth ssp. tetragona var. tetragona – Munz (1965); > Oenothera tetragona Roth ssp. tetragona var. velutina (Pennell) Munz – Munz (1965); > Oenothera tetragona Roth var. latifolia (Rydb.) Fernald – F, WV; > Oenothera tetragona Roth var. tetragona – F

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Heliophily: 8