Isozyme analysis of the Cerastium alpinum C-arcticum complex (Caryophyllaceae) supports a splitting of C-arcticum Lange

As part of a larger investigation of the C. alpinum-C. arcticum complex of arctic and North Atlantic areas, isozyme variation of C. alpinum, C. arcticum, and related taxa was analysed. A total of 124 multilocus phenotypes was divided into more or less distinct groups by numerical analyses. Most groups correspond well to previously recognized taxa. However, what has traditionally been considered as C. arcticum was divided into two distinct groups, consisting of northern (Svalbard, Greenland) and more southern (Norway, Iceland) populations, respectively. The division of C. arcticum into two taxa is also supported by other kinds of data and the two taxa probably deserve species rank. Serpentine plants from Shetland had multilocus phenotypes similar to those of C. arcticum from Iceland and should be included in the southern taxon.