On the germination, development, and fructification of the higher Cryptogamia : and on the fructification of the Coniferæ - Hofmeister, Wilhelm, 1824 -1877 (Published for the Ray Society, by Robert Hardwicke, 1862)

On the natural history of the Gulf of St. Lawrence and the distribution of the Mollusca of Eastern Canada - Bell, Robert, 1841 -1917 (s.n.], 1859)

On the organization of the fossil plants of the coal-measures Further observations on the organization of the fossil plants of the coal-measures - Williamson, William Crawford, 1816 -1895 (1894)

On the popular names of British plants : being an explanation of the origin and meaning of the names of our indigenous and most commonly cultivated species - Prior, R. C. Alexander (Richard Chandler Alexander), 1809 -1902 (F. Norgate; [etc., etc.], 1879)

On the popular names of British plants, being an explanation of the origin and meaning of the names of our indigenous and most commonly cultivated species - Prior, R. C. Alexander (Richard Chandler Alexander), 1809 -1902 (Williams & Norgate, 1863)

On the popular names of British plants, being an explanation of the origin and meaning of the names of our indigenous and most commonly cultivated species - Prior, R. C. Alexander (Richard Chandler Alexander), 1809 -1902 (Williams and Norgate, 1870)

One hundred seventh annual report of the New York State Museum (University of the State of New York, State Education Dept, 1944)

The Ontario natural science bulletin - Wellington Field Naturalists' Club. (Wellington Field Naturalists' Club, 1912)

Orchidaceae: illustrations and studies of the family Orchidaceae - Ames, Oakes, 1874 -1950 (Houghton, Mifflin, 1922)

Orchidaceele din România - Pantu, Zacharia C., 1866 -1934 (Librariile Socec & co. [etc.], 1915)

Oregon flora newsletter - Oregon State University. Department of Botany; Plant Pathology. (Oregon Flora Project, Dept. of Botany & Plant Pathology, Oregon State University, 1995)

Organographie der Pflanzen, insbesondere der Archegoniaten und Samenpflanzen - Goebel, K. (Karl), 1855 -1932 (G. Fischer, 1913)

Organographie der Pflanzen, insbesondere der Archegoniaten und Samenpflanzen - Goebel, K. (Karl), 1855 -1932 (G. Fischer, 1898)

Organographie der Pflanzen, insbesondere der Archegoniaten und Samenpflanzen - Goebel, K. (Karl), 1855 -1932 (G. Fischer, 1915)

Organography of plants, especially of the archegoniatae and spermaphyta - Goebel, K. (Karl), 1855 -1932 (Clar. Press, 1900)

The origin of a land flora : a theory based upon the facts of alternation - Bower, F. O. (Frederick Orpen), 1855 -1948 (Macmillan, 1908)

The origin of a land flora : a theory based upon the facts of alternation - Bower, F. O. (Frederick Orpen), 1855 -1948 (Macmillan and co., limited, 1908)