The Ohio naturalist - Ohio Academy of Science. (Biological Club of the Ohio State University, 1906)

Les Oiseaux d'Europe décrits par C. J. Temminck - Werner, Johann Carl. (1848)

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 parthenogenesis - Owen, Richard, 1804 -1892 (John Van Voorst, 1849)

On the fauna and flora of the west of Scotland. Meeting at Glasgow, September, 1876 - British Association for the Advancement of Science. (Blackie, 1876)

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 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 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)

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

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)

Opera e periodicis collata - Vries, Hugo de, 1848 -1935 (A. Oosthoek, 1918)

Der Organismus der Infusionsthiere - Stein, Friedrich, 1818 -1885 (W. Engelmann, 1859)

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, 1913)

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

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)

L'origine et le développement des flores dans le massif central de France; avec aperçu sur les migrations des flores dans l'Europe sud-occidentale - Braun-Blanquet, J. (Josias), 1884 -1980 (L. Lhomme, 1923)

Die Ostsudeten; eine floristische Skizze - Hruby, Johann. (Landesdurch-forschungs-Komemission, 1914)

O.S.U. naturalist - Ohio State University. Biological Club. (Biological Club of Ohio State University, 1902)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1899)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1903)

Our native ferns, or, A history of the British species and their varieties / by E.J. Lowe - Lowe, E. J. (Edward Joseph), 1825 -1900 (G. Bell & Sons, 1874)

Our native ferns; or, A history of the British species and their varieties - Lowe, E. J. (Edward Joseph), 1825 -1900 (Groombridge, 1865)

Outlines of botany for the high school laboratory and classroom (based on Gray's Lessons in botany) - Leavitt, Robert Greenleaf, 1865 - (American Book Co, 1901)

Outlines of classification and special morphology of plants - Goebel, K. (Karl), 1855 -1932 (Clarendon Press, 1887)

Outlines of classification and special morphology of plants - Balfour, Isaac Bayley, 1853 -1922 (Clarendon Press, 1887)

Outlines of comparative physiology : touching the structure and development of the races of animals, living and extinct, for the use of schools and colleges - Agassiz, Louis, 1807 -1873 (Bell & Daldy, 1867)

Outlines of comparative physiology : touching the structure and development of the races of animals, living and extinct : for the use of schools and colleges - Agassiz, Louis, 1807 -1873 (H.G. Bohn, 1851)

Pacific States Floral Congress. [Papers] - California State Floral Society. (Academy of sciences, 1901)

Une page d'histoire de la medecine : la thérapeutique sous les premiers Césars - Lépine, R. (Raphael), 1840 -1919 (F. Alcan, 1890)