Amplified fragment length polymorphism (AFLP) fingerprinting, was used to investigate relationships of northern European Dactylorhiza (Orchidaceae), which constitutes a complex of diploids and tetraploids. The autotetraploid Dactylorhiza maculata (4x) has arisen on more than one occasion from D. fuchsii (2x). This finding explains why tetraploid populations often closely approach D. fuchsii in morphology, and we propose that both ploidy levels should be accommodated in D. maculata s.l. Morphological variants of D. incarnata, often treated as distinct subspecies or even species, did not form monophyletic groups and are probably the result of variation at one or a few closely linked loci. These variants should be treated as D. incarnata s.l. A group of several allotetraploid taxa derived by hybridization between D. maculata s.l. and D. incarnata s.l. showed a complex pattern of relationships. Some of these allotetraploids have multiple origins, and we regard the allotetraploid group as a single 'species', D. majalis s.l., that is thus not only polyphyletic, but also polytopic in origin. The AFLP data agree with findings from previous isoenzyme studies, but provide much more detailed information, enabling us to present more strongly supported hypotheses. Thus, AFLPs are a powerful tool in elucidating detailed relationships in polyploid complexes, but further insights may be gained by combining these results with those from other methods, such as isoenzymes, that provide single-locus data.

Key words: AFLPs, Dactylorhiza incarnata, Dactylorhiza maculata, Dactylorhiza majalis, hybrid origins, Orchidaceae