Anders Thiodolf Saelan (Sælan) (born 20 November 1834 in Lappeenranta; died 24 June 1921 in Helsinki) was a Finnish physician and botanist.

[1] He reformed Finnish mental health care during his decades as chief physician of Lapinlahti Psychiatric Hospital in Helsinki.

[7][8] Saelan, at the time a young graduate, collaborated with William Nylander to publish Herbarium Musei fennici in 1859.

[9] This catalogue listed 1,025 species of vascular plants, 333 mosses, 316 lichens, 71 algae, and 375 fungi.

They had four children: Gertrud Maria (1875–1911), Karl Thorvald (1878–1959), Eva Johanna Paersch (1883–1966), and Sigyn Naemi Lindberg (1888–1965).