Oesterreichisches botanisches Wochenblatt ([L.W. Seidel], 1853)

Oesterreichisches botanisches Wochenblatt ([L.W. Seidel], 1854)

Official guide to the museums of economic botany. No. 1, Dicotyledons - Royal Botanic Gardens, Kew. (Printed for H.M. Stationery Off., by Darling, 1907)

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)

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 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, 1910)

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

L'Oiseau et la Revue francaise d'ornithologie - Société ornithologique de France. (Société ornithologique de France, 1988)

Les Ombellifères : contributions pluridisciplinaires à la systématique : actes du 2e Symposium International sur les Ombellifères, Centre Universitaire de Perpignan, 18-21 mai 1977 - Cauwet-Marc, A.-M. (Anne-Marie) (Missouri Botanical Garden, 1977)

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, 1993)

Oréades - Instituto de Ciências Biológicas da UFMG. Departamento de Botânica. (Departamento de Botânica, U.F.M.G, 1970)

Oréades - Instituto de Ciências Biológicas da UFMG. Departamento de Botânica. (Departamento de Botânica, U.F.M.G, 1972)

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)

Organic materia medica and therapeutics : in accordance with the sixth revision of the United States Pharmacopoeia - Simpson, James Young, Sir, 1811 -1870 (J.H. Vail, 1885)

The origin of species - Darwin, Charles, 1809 -1882 (Books, Inc, 1900)

The origin of species - Darwin, Charles, 1809 -1882 (Literary Classics, 1900)

The origin of species by means of natural selection, or, The preservation of favored races in the struggle for life - Darwin, Charles, 1809 -1882 (A.L. Burt, 1899)

The origin of species by means of natural selection, or, The preservation of favored races in the struggle for life - Darwin, Charles, 1809 -1882 (D. Appleton and Company, 1917)

The origin of species by means of natural selection : or The preservation of favored races in the struggle for life - Darwin, Charles, 1809 -1882 (Hurst, 1872)

Ornamental plant explorations, Japan, 1961 - United States. Agricultural Research Service. (Agricultural Research Service, U.S. Dept. of Agriculture in cooperation with Longwood Gardens of the Longwood Foundation, Inc, 1966)

The ornamental trees of Hawaii - Rock, Joseph F. (Joseph Francis), 1884 -1962 (1917)

Ornithological science - Nihon Chogakkai (Ornithological Society of Japan, 2002)

Our native trees and how to identify them : a popular study of their habits and their peculiarities - Keeler, Harriet L. (Harriet Louise), 1846 -1921 (C. Scribner's Sons, 1900)

Our native trees and how to identify them; a popular study of their habits and their peculiarities - Keeler, Harriet L. (Harriet Louise), 1846 -1921 (C. Scribner's Sons, 1917)

Our native trees and how to identify them; a popular study of their habits and their peculiarities - Keeler, Harriet L. (Harriet Louise), 1846 -1921 (Scribner, 1902)

Our northern shrubs and how to identify them; a handbook for the nature-lover - Keeler, Harriet L. (Harriet Louise), 1846 -1921 (C. Scribner, 1912)

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

An outline of plant geography (The Macmillan company, 1926)

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)

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, 1953)

Pacific science - University of Hawaii. (University Press of Hawaii, 1954)

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, 1962)

Pacific science - University of Hawaii. (University Press of Hawaii, 1963)

Pacific science - University of Hawaii. (University Press of Hawaii, 1967)

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

Palaeontology - Palaeontological Association (Palaeontological Association, 1966)

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

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1887)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1916)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1918)

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

Pamphlets on forestry in Texas (1900)

Pamphlets on silviculture (1899)

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, 1990)

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, 1994)

The Pan-Pacific entomologist - Van Duzee, Edward P. (Edward Payson), 1861 -1940 (Pacific Coast Entomological Society, 1998)

The Pan-Pacific entomologist - Van Duzee, Edward P. (Edward Payson), 1861 -1940 (Pacific Coast Entomological Society, 2002)

Papers and proceedings of the Royal Society of Tasmania - Royal Society of Tasmania. (The Society, 1874)

Park and cemetery - Haight, R. J. (Rufus J.) (R.J. Haight, 1898)

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

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

Peninsula Field Naturalists' Club Newsletter - Peninsula Field Naturalists' Club (Peninsula Field Naturalists' Club, 2015)

Peninsula Field Naturalists' Club Newsletter - Peninsula Field Naturalists' Club (Peninsula Field Naturalists' Club, 2020)

Peninsula Field Naturalists' Club Newsletter - Peninsula Field Naturalists' Club (Peninsula Field Naturalists' Club, 2022)

Perú: Cordillera Escalera-Loreto - Stotz, Douglas F. (Douglas Forrester), 1956 - (The Field Museum, Science and Education, 2014)

Peru : Ere-Campuya-Algodón - Field Museum of Natural History. (The Field Museum, Science and Education, 2013)

Peru : Maijuna - Alverson, William Surprison (Field Museum, Environment, Culture and Conservation, 2010)