Observations of a naturalist in the Pacific between 1896 and 1899 - Guppy, H. B. (Henry Brougham), 1854 -1926 (Macmillan and co., limited, 1903)

Observations on the flowering plants, ferns and fern allies growing wild in Marquette County, Michigan, in 1916 and 1917, especially in the vicinity of the Huron Mountain Club - University of Michigan. Museum of Zoology. (Published by the University, 1918)

Observations sur la végétation de l'ile de Sitcha - Bongard, H. G. (Heinrich Gustav), 1786 -1839 (s.n, 1833)

Occasional papers - San Diego Society of Natural History. (San Diego Society of Natural History, 1949)

Occasional Papers of the Bernice Pauahi Bishop Museum of Polynesian Ethnology and Natural History - Bernice Pauahi Bishop Museum. (Bishop Museum Press, 1906)

Occasional papers of the California Academy of Sciences - California Academy of Sciences (California Academy of Sciences, 1979)

Occasional papers of the California Academy of Sciences - California Academy of Sciences (California Academy of Sciences, 1993)

Occasional papers of the Farlow Herbarium of Cryptogamic Botany - Farlow Reference Library; Herbarium. (Harvard University, Farlow Herbarium of Cryptogamic Botany, 1980)

Oecology of plants : an introduction to the study of plant-communities - Vahl, M. (Martin), 1749 -1804 (Clarendon Press, 1909)

Oecology of plants : an introduction to the study of plant-communities - Warming, Eugenius, 1841 -1924 (Clarendon Press, 1909)

Oecology of plants; an introduction to the study of plant-communities - Balfour, Isaac Bayley, 1853 -1922 (Clarendon Press, 1909)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1862)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1883)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1889)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1897)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1898)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1899)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1900)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1902)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1903)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1904)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1905)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1907)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1908)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1909)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1910)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1911)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1912)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1913)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1915)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1916)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1918)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1919)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1920)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1921)

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, 1901)

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

Ohio Biological Survey notes - Ohio Biological Survey. (Ohio Biological Survey, 2017)

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

The Ohio journal of science - Ohio Academy of Science. (Ohio Academy of Science, 1912)

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, 1909)

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

The Ohio naturalist - Ohio Academy of Science. (Biological Club of the Ohio State University, 1913)

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, 1890)

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, 1875)

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 & Co., ltd, 1899)

On the causative factors responsible for the change in the bison range - Flerov, K. K. (1961)

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

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)

The Orchadian - Australasian Native Orchid Society (The Society, 1994)

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

Oregon flora newsletter - Oregon State University. Department of Botany; Plant Pathology. (Oregon Flora Project, Dept. of Botany & Plant Pathology, Oregon State University, 2000)

Oregon flora newsletter - Oregon State University. Department of Botany; Plant Pathology. (Oregon Flora Project, Dept. of Botany & Plant Pathology, Oregon State University, 2002)

Oregon flora newsletter - Oregon State University. Department of Botany; Plant Pathology. (Oregon Flora Project, Dept. of Botany & Plant Pathology, Oregon State University, 2005)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1908)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1909)

Our garden flowers; a popular study of their native lands, their life histories, and their structural affiliations - Keeler, Harriet L. (Harriet Louise), 1846 -1921 (C. Scribner's Sons, 1910)

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)

Overwash processes and foredune ecology, Nauset Spit, Massachusetts - Massachusetts Audubon Society. (U.S. Army Engineer Waterways Experiment Station, 1984)

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)

Palaeontographica (Theodor Fischer, 1902)

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, 1885)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1888)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1892)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1904)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1916)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1917)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1918)

Pamphlets on silviculture (1899)

The Pan-Pacific entomologist - Van Duzee, Edward P. (Edward Payson), 1861 -1940 (Pacific Coast Entomological Society, 1936)

The Pan-Pacific entomologist - Van Duzee, Edward P. (Edward Payson), 1861 -1940 (Pacific Coast Entomological Society, 1972)

The Pan-Pacific entomologist - Van Duzee, Edward P. (Edward Payson), 1861 -1940 (Pacific Coast Entomological Society, 1993)

The Pan-Pacific entomologist - Van Duzee, Edward P. (Edward Payson), 1861 -1940 (Pacific Coast Entomological Society, 1995)

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

Peace parkland native grassland stewardship program 2001/02 - Alberta. Fish; Wildlife Division. (Alberta Sustainable Resource Development, Fish & Wildlife Division, Resource Data and Species At Risk Section, 2004)