Morphological and electrophoretic variation has been documented within and among populations of Salicornia europaea L. (s.l.) in northeastern North America. Univariate and multivariate analyses (discriminant analyses) of measurements of floral and vegetative characters delimited three morphologically distinct groups of populations: Atlantic coast tetraploids (2n = 36), Hudson Bay diploids, and Atlantic coast and James Bay diploids (2n = 18). The two diploid groups were morphologically distinct from the midwestern diploid, S. rubra Nels., based on anther length, width of the scarious border of the fertile segment, and the overall width of the fertile segment. Electrophoretic evidence supported the delimitation of the three distinct morphological groups of populations of S. europaea with the exception of the population from James Bay, which had electrophoretic patterns identical with those of plants from Hudson Bay but resembled the Atlantic coast diploids morphologically. Most enzyme systems assayed were monomorphic. Only homozygous banding patterns were detected in diploid plants and electrophoretic variation was not observed within populations of S. europaea or S. rubra but was detected between groups of populations. Four multilocus phenotypes were evident; these corresponded to the major groups recognized on the basis of ploidy level and morphology. Reasons that may account for the paucity of isozymic variation are discussed.
