The work which led to the recognition of Adiantum viridimontanum as a distinct taxon began in the early 20th century. Following the discovery of disjunct specimens of western maidenhair fern, then classified as A. pedatum var. aleuticum, on the serpentine tableland of Mount Albert by Merritt Lyndon Fernald in 1905, botanists began to search for western maidenhair on ultramafic outcrops elsewhere in Quebec and Vermont. It was first identified in Vermont by L. Frances Jolley in 1922 at Belvidere Mountain in Eden. In 1983, William J. Cody transferred A. pedatum growing on serpentine, both in eastern and western North America, to A. pedatum subsp. calderi instead. Many of the stations for the fern in Vermont were described in 1985, in a survey of ultramafic outcrops in that state.