Flora of the prairies and plains of central North America.

by Rydberg, Per Axel, 1860-1931
Published 1965

Flora of Colorado /

by Rydberg, Per Axel, 1860-1931
Published 1906

Flora of the southeastern United States ; being descriptions of the seed-plants, ferns and fern-allies growing naturally in North Carolina, South Carolina, Georgia, Florida, Tennes...

by Small, John Kunkel, 1869-1938
Published 1913

Catalogue of the flora of Montana and the Yellowstone National Park /

by Rydberg, Per Axel, 1860-1931
Published 1900

Flora of the Rocky mountains and adjacent plains : Colorado, Utah, Wyoming, Idaho, Montana, Saskatchewan, Alberta, and neighboring parts of Nebraska, South Dakota, North Dakota, an...

by Rydberg, Per Axel, 1860-1931
Published 1954