Otto Stapf FRS (23 April 1857 in Perneck near Bad Ischl - 3 August 1933 in Innsbruck) was an Austrian born botanist and taxonomist, the son of Joseph Stapf, who worked in the Hallstatt salt-mines. He grew up in Hallstatt and later published the archaeological plant remains from the Late Bronze- und Iron Age mines that had been uncovered by his father.Stapf studied Botany in Vienna under Julius Wiesner, where he received his PhD with a dissertation on cristals and cristalloids in plants.