Aimo Kaarlo Cajander (1879–1943) was, outside of Botanics, best known as Prime Minister of Finland up to the Winter War.

He was a professor of Forestry 1911–34; director-general for Finland's Forest and Park Service 1934–1943; prime minister in 1922, 1924, and 1937–1939; chairman of the National Progressive Party 1933–1943; and Member of Parliament.

Cajander's name is remembered for "Model Cajander", the fashion of many Finnish soldiers in Winter War: the army was poorly equipped, so a conscript man was given a utility belt, an emblem to be attached to the hat — to comply with the Hague Conventions (1899 and 1907) — and, hopefully, a rifle. Otherwise, he had to use his own clothes and equipment.

|- style="text-align: center;" | width="30%" |Preceded by:
Kyösti Kallio | width="40%" style="text-align: center;" |Prime Minister of Finland
1924 | width="30%" |Succeeded by:
Lauri Ingman

|- style="text-align: center;" | width="30%" |Preceded by:
Kyösti Kallio | width="40%" style="text-align: center;" |Prime Minister of Finland
1937–1939 | width="30%" |Succeeded by:
Risto Ryti