The Ohio naturalist - Ohio Academy of Science. (Biological Club of the Ohio State University, 1904)

The Ohio naturalist - Ohio Academy of Science. (Biological Club of the Ohio State University, 1903)

The Ohio naturalist - Ohio Academy of Science. (Biological Club of the Ohio State University, 1909)

On molecular and microscopic science - Somerville, Mary Fairfax, 1780 -1872 (J. Murray, 1869)

On molecular and microscopic science - Somerville, Mary, 1780 -1872 (J. Murray, 1869)

On the forms and structure of fern-stems - Ogilvie, George, 1820 -1886 (Taylor and Francis, 1859)

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 germination, development, and fructification of the higher Cryptogamia, and on the fructification of the Coniferae - Hofmeister, Wilhelm, 1824 -1877 (Pub. for the Ray society by R. Hardwicke, 1862)

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)

Onze flora. Beschrijving van de familiën, voornamste geslachten en soorten der in Nederland in het wild groeiende, verwilderde, verbouwde en aangeplante gewassen, alsmede van eenige fraaie en nuttige midden-europeesche planten - Hoffmann, Carl, 1802 -1883 (W.J. Thieme, 1900)

The Orchadian - Australasian Native Orchid Society (The Society, 1969)

The Orchadian - Australasian Native Orchid Society (The Society, 1977)

The Orchadian - Australasian Native Orchid Society (The Society, 1963)

Die organischen Regulationen, Vorbereitungen zu einer Theorie des Lebens - Driesch, Hans, 1867 -1941 (Engelmann, 1901)

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)

Organographie vegetale ; ou, Description raisonnee des organes des plantes, pour servir de suite et de developpement a la theorie elementaire de la botanique, et d'introduction a la physiologie vegetale et a la description des familles, avec 60 planches en taille-douce - Candolle, Augustin Pyramus de, 1778 -1841 (Chez Deterville, libraire, rue Hautefeuille, no.8, 1827)

Organography of plants, especially of the Archegoniata and Spermaphyta - Balfour, Isaac Bayley, 1853 -1922 (Clarendon press, 1900)

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)