Hackberry-leaf Goldenrod

Solidago rugosa var. celtidifolia (Small) Fern. is native to sandy and silty soils, fields, woods and wet ground on the coastal plain of the southeastern U.S. from southeastern Virginia to eastern Texas.  It is distinguished by its moderately to densely hairy, sometimes sharply-toothed, ovate, upper stem leaves, which are much reduced upward (Semple & Cook 2006 FNA).  Some plants in the northeastern part of the range are difficult to distinguish from var. aspera, while in Louisiana some plants are very distinct.  The variety includes both diploids and tetraploids (2n=18, 2n=36).

The variety was first described as Solidago celtidifolia Small from southern Mississippi. When a population consists of extreme forms such as illustrated from Louisiana, it is easy to see why botanists might view the taxon as a distinct species.  Having sampled the taxon over most of its range in the field, I find the extreme forms to be the end of a continuum in variation.  I have considered breaking up the S. rugosa complex into separate species, but favour retaining all forms in a single species in this case.