Peat mosses (Sphagnaceae) are ideal model organisms to explore the limits of morphological adaptation due to both their relative phylogenetic isolation and the reproducibility of their thallus growth in vitro. In the present study, we have systematically investigated the effect of supplemental cytokinin and sucrose on the gametophyte development of Sphagnum fallax, S. fimbriatum, and S. quinquefarium. Culture media supplemented with 6-benzyl aminopurine (BAP, 0.6 mg/l) induced substantial changes in the morphology of the protonema and significantly enhanced bud formation. Among other effects, BAP increased the production of unicellular hairs, which are newly described for Sphagnum. In some cases, 0.5% sucrose added to the effect of BAP. Taken together, our data demonstrate that some cytokinin effects known from other mosses also occur in Sphagnum, but they also reveal some new features of the unique Sphagnum phenotype.