The reproductive biology of Arethusa bulbosa, Calopogon tuberosus, and Pogonia ophioglossoides was studied in northern Wisconsin. The three species possess a number of floral characters suggesting convergence, yet they remain distinct as a result of isolating mechanisms. Convergence is suggested mainly by the size of the flowers, pink-magenta perianth, lips with yellow-white brushes, and strong absorption of ultraviolet light by the lip brushes. Some of the isolating mechanisms between the species are placement of pollen on the insects, partial seasonal isolation, and chromosomal size and number. The pollinators are various species of bees.