A new speices of Orthotrichum is described from Tuva Republic, South Siberia. It is similar to O. obtusifolium and O. gymnostomum in obtuse leaf and abundant gemmae produced on leaf surface. However O. furcatum Otnyukova sp. nov. differs from them in high and (2-)3(-4)-forked papillae on both sides, one per cell, its leaf margin crenulate in the upper half of leaf due to large papillae on marginal cells.