Three rare Orthotrichum species, O. callistomum Fischer-Ooster ex Bruch, O. vladikavkanum Vent. and O. sordidum Sull. et Lesq., are documented with recent collections from the Russian Caucasus Mountains. Orthotrichum callistomum is a highly disjunct species, previously known from SE Asia (from Taiwan to Eastern Himalayas) and a single site in Switzerland (from 1849); O. vladikavkanum was described from Ossetiya in 1887, but was never recorded in Caucasus during XX century. Ortothichum sordidum also was found 1887, and only recently recorded again.