Genetic and morphological variation in the rare epiphytic moss Neckera pennata Hedw.

Fifteen Swedish populations of the threatened epiphytic moss Neckera pennat a Hedw. were surveyed for genetic variation by use of enzyme electrophoresi s. Seven genotypes were detected from 12 scored loci. The genotypes could b e divided into two groups, with specific alleles at four loci. The genetic identity between the genotype groups (0.641) is comparable to identities be tween congeneric species based on previous studies of mosses. Moreover, the se groups occurred sympatrically with no apparent sexual recombination, imp lying the possibility of sibling speciation. A morphological analysis revea led minor differences between the genotype,groups. Possible reasons for the lack of recombinant genotypes are discussed. In addition, genetic and morp hological analyses were performed to compare N. pennata and N. oligocarpa B ruch, which are considered distinct species by some bryologists and varieti es of the same species by others. Clear morphological differences and a gen etic differentiation of the same magnitude as the genotype groups of N. pen nata were revealed.