The extent of clonality in large stands of Lycopodium annotinum L.

In the Rothaargebirge (Northrhine-Westphalia) the interrupted club moss (Lycopodium annotinum L.) often grows in large (maximum size of patches observed: 18,000 m²) and dense (club moss cover 60–90%) clusters. By DNA amplification fingerprinting (DAF) analysis it was shown in three populations comprising a total of 69 samples that the clusters are of great genetical uniformity. Based on data from 47 polymorphic loci amplified with 13 primers 11 multilocus genotypes were identified, nine in one population and one per population in the other two. The data were subjected to similarity analysis, generating Jaccard′s similarity coefficients, on the basis of which cluster analysis was performed. Calculation of Nei's genetic diversity (1987) resulted in a mean value of 0.77 over all samples and a mean within populations diversity of 0.3. Corrected G′_ST value for the fraction of diversity among the populations was 0.7. Two out of three sites are most probably formed by one clone only. As the annual growth rate of the shoots is known, it has to be stated that the stands under investigation are at least 80–90 years old. Taking into consideration that annual accretion is virtually non-existent following forest thinning measures, it becomes very likely that the club moss plants are approximately as old as the trees of their forests (150–180 years). This hypothesis is supported by the observation that within the forests only large (i.e. old) stands, but no single shoots (i.e. young individuals) of the club moss exist. Thus one can conclude that in undisturbed forests no sexual reproduction of L. annotinum takes place.