Matango (1963) IMDb
Seen in 2013.
Review refers to the American dub, called Attack of the Mushroom People.
Held together by the idea of the alien half-vegetable ecology. This threat induces an apparently real happiness. Based on The Voice in the Night (1907) by William Hope Hodgson, who also wrote The Night Land (1912). A sequel on a larger scale, in the vein of A Scent of New-Mown Hay (1958) by John Blackburn, could be great.
References here: The Parasite Murders (1975).