Note:  Some scholars considered Solidago canadensis and Solidago altissima to be variations of the same species.  The current thinking - in Flora of North America and elsewhere - is that though they are very closely related, they are not the same species.  S. altissima is usually much taller, stouter and more pubescent than S. canadensis.  Also, though both are colonial from rhizomes, the colonies of S. altissima are capable of becoming vastly larger than those of S. canadensis.  The dense pubescence of S. altissima gives the foliage a slight gray-green color that is lacking in S. canadensis.  Most texts are in agreement that the leaves of S. canadensis are more prominently toothed than those of S. altissima.  However, I have seen some plants that have nearly untoothed leaves, but possess the characteristics of S. canadensis otherwise.

There are two variations of S. canadensis in New England:  var canadensis and var hargeri.  Var hargeri is distinguished primarily by the more dense stem pubescence, but otherwise is similar to var canadensis.

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