A flora of North America ?containing abridged descriptions of all the known indigenous and naturalized plants growing north of Mexico, arranged according to the natural system /by John Torrey and Asa Gray.
A manual of the botany of the northern United States,from New England to Wisconsin and south to Ohio and Pennsylvania inclusive, (the mosses and liverworts by Wm. S. Sullivant,) arranged according to the natural system.
A Manual of the Botany of the Northern United States.