The single species, Florissantia elegans, was described by Samuel Hubbard Scudder (1890) from fossils found in the Florissant Formation of Colorado.

[3] When described, the genus Florissantia was known from two separate fossils preserved as impressions in fine shales of the Florissant formation in Colorado.

[1] The formation is composed of successive lake deposits resulting from a volcanic debris flow damming a valley.

[6][7] The Florissant paleoforest surrounding the lake has been described as similar to modern southeastern North America, with a number of taxa represented that are now found in the subtropics to tropics and confined to the old world.

MacGinitie (1953) suggested a warm temperate climate based on the modern biogeographic relatives of the biota found in the formation.