Reproductive Success of Dactylorhiza fuchsii (Druce) Soó at the Northern Border of Its Distribution Range

Data on the population structure, morphometric features of plants and seeds, and some features of reproductive biology (fruit set and seed productivity) of Dactylorhiza fuchsii (Druce) Soó (Orchidaceae) on the northern border of the species distribution range (Komi Republic, northeast Russia) are presented. The seed size and flower number per inflorescence decrease significantly from south to north within the species range. In the Komi Republic, the seed productivity of Dactylorhiza fuchsii is lower compared to the southern parts of its range: one fruit contains, on average, 2900 ± 80 seeds, the average real seed productivity of the generative plant is 24 800 seeds. Despite the decrease in some indicators of reproductive success, the species forms quite large, well-renewing populations in the northern part of the areal.