NOTES ON THE TREATMENT OF THE FAMILY LYCOPODIACEAE FOR FLORA-NORDICA

The treatment of the family Lycopodiaceae as it will appear in the for thcoming Flora Nordica is discussed. Huperzia selago, Lycopodium annot inum and L. clavatum, Diphasiastrum complanatum, D. tristachyum and D. zeilleri exhibit wide morphological variation and sharp distinctions between the extreme forms cannot be made; a large number of intermedia te populations bind the extremes together. To some degree, the morphol ogical variation is caused by ecological, modificative and/or ecotypic al factors. The populations are nevertheless formed by clones, varying in age from very young to hundreds of years. In addition, vegetative reproduction of the clones is effective. Modern treatments confirm the role of hybridization in Lycopodiaceae. Fertilization may take place between archegonia and antheridia of a single prothallium, two prothal lia of the same taxon or the prothallia of two different taxa; also se lf-sterility may occur. Spores of the assumed hybrids in Finland are o nly partly abortive and thus the possibility of introgression cannot b e excluded, until it has shown not to be present. The effective distri bution of spores by wind is an additional factor to add to the confusi on. The distribution of the taxa is explained by the clonal structure of the species, the age of clones, the effective vegetative reproducti on and the effective distribution of the spores. Some geographical dis tinction is apparent, however. Eight species in four genera are recogn ized for the Flora Nordica. The northern races of four of the species are treated at subspecific level.