This largely northeastern tetraploid has been reported south to n. Ga., ne. Tenn. and n. Mo., but it occurs mostly in coastal regions from N.J. to Nfld., with few records far inland (F, Cr; Lewis 2008). There have been several reports of this species from Ky. (M, J), but most have been based on misidentifications. Clark et al. (2005; see also CW) reported colls. from six counties. The coll. from ROWA (EKY), at least, is verified here: E.M. & E.T. Browne #10492, 28 Jun 1965, from roadsides/fallow land 0.6 mi W of Haldeman P.O. on Ky 174. Apparent hybrids with carolina are known (X novae-angliae W.H. Lewis), and differences are not obvious in some colls. However, virginiana appears to have originated from the diploid, palustris (Joly & Bruneau 2007). Compared to carolina, virginiana becomes an upright taller plant, usually to 2 m (versus somewhat pendent, up to 1 m), and is much less colonial. Its infrastipular thorns are more or less curved and taper gradually from relatively stout flattened bases (versus straight or declining, less tapering, slender, terete); also, acicular thorns are generally concentrated or restricted to stem bases (versus often numerous on upper branches). Its stipules tend to be more dilated upwards into broader lanceolate tips that are less divergent; adnate portions are usually 4-9 mm wide (versus 1-4 mm). Its leaflets are usually 7-9 (versus 3-7), clearly lustrous (versus dull to slightly lustrous). Its corymbs have up to 6 (15) flowers (versus 3 (6)), with more than one often on stems of the season (versus usually solitary); sepals are up to 20 mm (versus 12 mm).