Morphological variation of the introduced perennial Solidago canadensis L sensu lato (Asteraceae) in Europe

Morphological and life-history variation within and between 23 European populations of the introduced and widespread perennial Solidago canadensis L. sensu lato (Asteraceae) was investigated. The populations differed significantly in all 19 characters measured. Coefficients of variation and intraclass-correlations were high for characters related to growth. Floral characters (involucral height, number of disks florets, number of ray florets), and pubescence of stems and leaves varied considerably among sampled shoots, but their frequently distributions were unimodal and the coefficients of variation low. The first three principal components explained 48% of the variation and formed no clusters among the shoots. Several characters means correlated with latitude, indicating clinal variation among the populations. Comparison of variation in floral and leaf characters with data from the native range suggests that S. canadensis s.l. naturalized in Europe belongs to a taxon that is close to S. canadensis var. scabra (Muhl.) Torr & Gray (S. altissima L.), despite the reported diploid chromosome number of this taxon in Europe. (C) 1998 The Linnean Society of London.