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

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 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 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, 1910)

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, 1912)

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

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

On the Apocynaceae of South America, with some preliminary remarks on the whole family ... - Miers, John, 1789 -1879 (Williams and Norgate, 1878)

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, 2002)

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)

Oréades - Instituto de Ciências Biológicas da UFMG. Departamento de Botânica. (Departamento de Botânica, U.F.M.G, 1974)

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)

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

Florist's journal (How and Parsons, 1844)

Florist's journal (How and Parsons, 1846)

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

Our early wild flowers : a study of the herbaceous plants blooming in early spring in the northern states - Keeler, Harriet L. (Harriet Louise), 1846 -1921 (Scribner, 1916)

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

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

Outline of the flora of Trinidad - Crüger, Herman, 1818 -1864 (Peter and Galpin, 1858)

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)

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, 1947)

Pacific science - University of Hawaii. (University Press of Hawaii, 1949)

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, 1955)

Pacific science - University of Hawaii. (University Press of Hawaii, 1956)

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, 1967)

Palaeontographica (Theodor Fischer, 1846)

Palaeontology - Palaeontological Association (Palaeontological Association, 1984)

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

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1888)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1892)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1917)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1896)

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

Pamphlets on forest utilization (1900)

Pamphlets on silviculture (1899)

The Pan-Pacific entomologist - Van Duzee, Edward P. (Edward Payson), 1861 -1940 (Pacific Coast Entomological Society, 1971)

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, 1978)

The Pan-Pacific entomologist - Van Duzee, Edward P. (Edward Payson), 1861 -1940 (Pacific Coast Entomological Society, 1982)

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, 1995)

Papaya - Ram, Mansha. (Indian Council of Agricultural Research, 2009)

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

Paxton's magazine of botany, and register of flowering plants - Paxton, Joseph, Sir, 1803 -1865 (Orr and Smith [etc.], 1849)

The periodicity and distribution of radial growth in trees and their relation to the development of "annual" rings - Grossenbacher, John Gasser, 1875 - (1915)

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)