The Jardin botanique Nicolas Boulay at the university is named in his honor.
He was the author of numerous books and articles in the fields of bryology and paleobotany.
The fossil pteridosperm genus Boulayatheca bears his name, as does the bryophyte genus Boulaya, being circumscribed by Jules Cardot in 1912.
In addition to bryological/paleobotanioal research, he performed taxonomic work involving the genus Rubus.