Die officinellen Pflanzen der Pharmacopoea Germanica für Pharmaceuten und Mediciner besprochen und durch Originalabbildungen erläutert - Kohl, F. G. (Friedrich Georg), 1855 -1910 (Barth, 1895)

Die offizinellen Pflanzen und Drogen :eine systematische Übersicht über die in sämtlichen Staaten Europas sowie in Japan und den Vereinigten Staaten von Amerika offizinellen Pflanzen und Drogen mit kurzen erläuternden Bemerkungen - Mitlacher, Wilhelm, 1872 -1913 (C. Fromme, 1912)

Öfversigt af Finska vetenskaps-societetens förhandlingar - Suomen Tiedeseura (s.n.], 1905)

Öfversigt af Kongl. Vetenskaps-akademiens forhandlingar - Kungl. Svenska vetenskapsakademien. (P. A. Norstedt & Söner, 1850)

Ohio Biological Survey notes - Ohio Biological Survey. (Ohio Biological Survey, 2015)

The Ohio journal of science - Ohio Academy of Science. (Ohio Academy of Science, 1909)

The Ohio naturalist - Ohio Academy of Science. (Biological Club of the Ohio State University, 1905)

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

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, 1907)

The Ohio naturalist - Ohio Academy of Science. (Biological Club of the Ohio State University, 1910)

The Ohio naturalist - Ohio Academy of Science. (Biological Club of the Ohio State University, 1911)

Oikos= boletín del Centro de Ecología [UNAM] (Instituto de Ecología, UNAM, 2017)

On British wild flowers considered in relation to insects - Lubbock, John, Sir, 1834 -1913 (Macmillan, 1909)

On British wild flowers considered in relation to insects - Lubbock, John, Sir, 1834 -1913 (Macmillan, 1890)

On British wild flowers considered in relation to insects - Lubbock, John, Sir, 1834 -1913 (MacMillan, 1890)

On buds and stipules - Lubbock, John, Sir, 1834 -1913 (K. Paul, Trench, Trübner, 1899)

On the physical features of the central part of British North America and on its capabilities for settlement - Hector, James, Sir, 1834 -1907 (s.n.], 1861)

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)

Opmerkingen over eene Buitenzorgsche Kritiek op mijne Exkursionsflora von Java : verweerschrift, op last van den Hoofdinspecteur-Chef van den Dienst van het Boschwezen van Nederlandsch-Indië - Koorders, Sijfert Hendrik, 1863 -1919 (G. Kolff, 1914)

Opuscules de botanique (1862-1873) - Jussieu, Antoine Laurent de, 1748 -1836 (1875)

The Orchadian - Australasian Native Orchid Society (The Society, 1964)

Oréades - Instituto de Ciências Biológicas da UFMG. Departamento de Botânica. (Departamento de Botânica, U.F.M.G, 1977)

Oréades - Instituto de Ciências Biológicas da UFMG. Departamento de Botânica. (Departamento de Botânica, U.F.M.G, 1981)

The organic constituents of higher plants: their chemistry and interrelationships - Robinson, Trevor. (Burgess Pub. Co, 1963)

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)

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

Our South African flora = Ons Suid-Afrikaanse plantegroei - Compton, R. H. (Cape Times, 1900)

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)

Oxford gardens, based upon Daubeny's Popular guide to the physick garden of Oxford: with notes on the gardens of the colleges and on the University park - Gunther, R. T. (Robert Theodore), 1869 -1940 (Parker & son; [etc., etc.], 1912)

Oxford gardens. Based upon Daubeny's Popular guide to the physick garden of Oxford : with notes on the gardens of the colleges and on the University Park - Gunther, R. T. (Robert Theodore), 1869 -1940 (Parker, 1912)

Pacific science - University of Hawaii. (University Press of Hawaii, 1950)

Pacific science - University of Hawaii. (University Press of Hawaii, 1951)

Pacific science - University of Hawaii. (University Press of Hawaii, 1952)

Pacific science - University of Hawaii. (University Press of Hawaii, 1955)

Pacific science - University of Hawaii. (University Press of Hawaii, 1959)

Pacific science - University of Hawaii. (University Press of Hawaii, 1960)

Pacific science - University of Hawaii. (University Press of Hawaii, 1966)

Pacific science - University of Hawaii. (University Press of Hawaii, 1968)

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

Paleobotany and biogeography : a festschrift for Alan Graham in his 80th year - Raven, Peter H (Missouri Botanical Garden, 2014)

Palladin's Plant physiology - Hopping, Aleita, 1890 - (P. Blakiston's son, 1926)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1883)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1885)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1887)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1892)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1895)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1896)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1904)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1918)

[Pamphlets on agriculture in Guam] (s.n, 1905)

Pamphlets on silviculture (1899)

The Pan-Pacific entomologist - Van Duzee, Edward P. (Edward Payson), 1861 -1940 (Pacific Coast Entomological Society, 1952)