Orchard and garden (J.T. Lovett, 1889)

Orchis :Monatsschrift der Deutschen Gesellschaft für Orchideenkunde - Dammer, Udo. (1915)

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)

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

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

Outlines of British fungology; containing characters of above a thousand species of Fungi, and a complete list of all that have been described as natives of the British Isles - Berkeley, M. J. (Miles Joseph), 1803 -1889 (L. Reeve, 1860)

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

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

Oversigt over det Kongelige Danske videnskabernes selskabs forhandlinger = Bulletin de l'Académie royale des sciences et des lettres de Danemark - Kongelige Danske videnskabernes selskab. (A.F. Høst, 1884)

Oversigt over det Kongelige Danske videnskabernes selskabs forhandlinger = Bulletin de l'Académie royale des sciences et des lettres de Danemark - Kongelige Danske videnskabernes selskab. (A.F. Høst, 1896)

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

Die palaeobotanische Literatur : bibliographische Übersicht über die Arbeiten aus dem Gebiete der Palaeobotanik - Jongmans, W. (Willem), 1878 -1957 (Fischer, 1910)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1891)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1914)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1916)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1918)

Pamphlets on forest protection (1900)

Pamphlets on forestry in North Dakota and South Dakota (1900)

Papers and proceedings of the Royal Society of Tasmania - Royal Society of Tasmania. (The Society, 1898)

Papers presented at the Celebration of the Twentieth Anniversary of the New York Botanical Garden, September 6-9, 1915. Published by the aid of the David Lydig Fund, bequethed by Charles P. Daly - New York Botanical Garden (1916)

Parasitic fungi of Illinois / by T.J. Burrill - Earle, F. S. (Franklin Sumner), 1856 -1929 (J. W. Franks, 1885)

I parassiti vegetali delle piante coltivate od utili - Ferraris, Teodoro. (Sineo & Bo, 1913)

Part I. The living flora of West Virginia - Millspaugh, Charles Frederick, 1854 -1923 (Wheeling news litho. co, 1913)

Pathological plant anatomy - Küster, Ernst, 1874 -1953 (1913)

Pathologie interne - Cadéac, Célestin, 1858 -1952 (J.B. Baillière, 1908)

Pathologie interne - Cadéac, Célestin, 1858 -1952 (J.B. Baillière, 1909)

Pathologische Pflanzenanatomie. In ihren Grundzügen - Küster, Ernst, 1874 -1953 (G. Fischer, 1916)

Patologia vegetale. Fanerogame parassite, mixomiceti, bacterii, ifomiceti od eumiceti (funghi) - Voglino, Pietro. (Unione tipografico-editrice [Gia ditta Pomba e c], 1905)

Pesticides documentation bulletin - National Agricultural Library (U.S.) (National Agricultural Library, U.S. Dept. of Agriculture, #c 1965-1969, 1965)