Elias Magnus Fries (August 15, 1794 – February 8, 1878) was a Swedish mycologist and botanist born at Femsjö in Småland.
Fries is considered to be, after Persoon, founding father of modern mushroom taxonomy (see mycology). His taxonomy of mushrooms was influenced by German romantics (see Goethe). He utilized spore color and arrangement of the hymenophore (pores, gills, teeth etc.) as major taxonomic characteristics.
When he died, The Times commented: "His very numerous works, especially on fungi and lichens, give him a position as regards those groups of plants only comparable to that of Linnaeus." (The Times, Thursday, Feb 21, 1878; pg. 6; Issue 29184; col C)
Fries was succeeded in the borgströmian professorship by John Areschoug, after whom Thore Fries, the son of Elias, held the chair.