Observing, photographing, and collecting plants - Illinois. Natural History Survey Division (Illinois Natural History Survey, 1980)

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

Oesterreichische botanische Zeitschrift (A. Skofitz, 1859)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1886)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1905)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1914)

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 journal of science - Ohio Academy of Science. (Ohio Academy of Science, 1916)

The Ohio journal of science - Ohio Academy of Science. (Ohio Academy of Science, 1917)

The Ohio journal of science - Ohio Academy of Science. (Ohio Academy of Science, 1920)

The Ohio journal of science - Ohio Academy of Science. (Ohio Academy of Science, 1921)

The Ohio naturalist - Ohio Academy of Science. (Biological Club of the Ohio State University, 1900)

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, 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, 1913)

Oikos= boletín del Centro de Ecología [UNAM] (Instituto de Ecología, UNAM, 2014)

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

The old and the new in corn culture - Biggar, H. Howard (Harvey Howard), 1886 - (U.S. Dept. of Agriculture, 1918)

Old civilizations of Inca land - Mead, Charles W. (Charles Williams), 1845 -1928 (American Museum Press, 1942)

Old civilizations of Inca land - Mead, Charles W. (Charles Williams), 1845 -1928 (American Museum of Natural History, 1924)

Old civilizations of Inca land - Mead, Charles W. (Charles Williams), 1845 -1928 (American museum of natural history, 1932)

Old time gardens - Earle, Alice Morse, 1851 -1911 (The Macmillan company, 1901)

Old time gardens : newly set forth - Earle, Alice Morse, 1851 -1911 (The Macmillan Company, 1901)

Old time gardens, newly set forth - Earle, Alice Morse, 1851 -1911 (Macmillan, 1922)

Old time gardens, newly set forth - Earle, Alice Morse, 1851 -1911 (The Macmillan Company, 1901)

On the structure of the pistils of some grasses - Walker, Elda Rema (1906)

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The onion (ICAR-Directorate of Knowledge Management in Agriculture, Indian Council of Agricultural Research, 2015)

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

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Oregon flora newsletter - Oregon State University. Department of Botany; Plant Pathology. (Oregon Flora Project, Dept. of Botany & Plant Pathology, Oregon State University, 1997)

Oregon flora newsletter - Oregon State University. Department of Botany; Plant Pathology. (Oregon Flora Project, Dept. of Botany & Plant Pathology, Oregon State University, 2007)

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

Organic livestock farming - Indian Council of Agricultural Research. Directorate of Knowledge Management in Agriculture. (Directorate of Knowledge Management in Agriculture, Indian Council of Agricultural Research, 2013)

Organization of repetitive DNA in the primitive reptile (Sphenodon Punctatus) - Van Den Bussche, Ronald A. (Museum of Texas Tech University, 1998)

Origin of cultivated plants - Candolle, Alphonse de, 1806 -1893 (Hafner Pub. Co, 1890)

Origin of cultivated plants - Candolle, Alphonse de, 1806 -1893 (D. Appleton, 1886)

Origin of cultivated plants - Candolle, Alphonse de, 1806 -1893 (Appleton, 1892)

Origin of cultivated plants - Candolle, Alphonse de, 1806 -1893 (D. Appleton and Co, 1908)

Origin of cultivated plants - Candolle, Alphonse de, 1806 -1893 (K. Paul, Trench, 1884)

Origin of cultivated plants - Candolle, Alphonse de, 1806 -1893 (Paul, Trench, 1886)

Origin of cultivated plants - Candolle, Alphonse de, 1806 -1893 (D. Appleton, 1885)

Origin of cultivated plants - Candolle, Alphonse de, 1806 -1893 (D. Appleton and company, 1902)

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

Ornithologische Monatsschrift - Deutscher Verein zum Schutze der Vogelwelt. (Kommissions-Verlag der Creutschen Verlagsbuchhandlung, 1907)

O.S.U. naturalist - Ohio State University. Biological Club. (Biological Club of Ohio State University, 1901)

O.S.U. naturalist - Ohio State University. Biological Club. (Biological Club of Ohio State University, 1903)

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

Outlines of medical botany :comprising vegetable anatomy and physiology...and a glossary of terms - Reid, Hugo. (Maclachlan, Stewart & Co, 1896)

The outlines of the veterinary art; or, The principles of medicine : as applied to the structure, functions, and economy, of the horse, and to more scientific and successful manner of treating his various diseases : comprehending, also, a concise view of those of neat cattle and sheep... - Blaine, Delabere P. (Delabere Pritchett), 1770 -1845 (Printed for Boosey & Sons, 1826)

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

Pacific science - University of Hawaii. (University Press of Hawaii, 1958)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1885)

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

Pamphlets on forest protection (1900)

Pamphlets on forestry in California (1900)

Pamphlets on forestry in New York (1900)

Pamphlets on silviculture (1899)

The Pan-Pacific entomologist - Van Duzee, Edward P. (Edward Payson), 1861 -1940 (Pacific Coast Entomological Society, 1959)

The Pan-Pacific entomologist - Van Duzee, Edward P. (Edward Payson), 1861 -1940 (Pacific Coast Entomological Society, 1977)

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)

Papilio - Edwards, Henry, 1827 -1891 (New York Entomological Club, 1884)

Parasitic rhizoctonias in America - Peltier, George Leo, 1888 - (1916)

Pasture grasses and forage plants, and their seeds, weeds, and parasites - Preston, Samuel P. (T. C. Jack, 1887)

The pathogenicity and interrelationship of Pratylenchus coffeae and Phythium splendens on Chinese evergreen - Noegel, Kenneth Arlen, 1938 - (1972)

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

Paxton's magazine of botany, and register of flowering plants - Paxton, Joseph, Sir, 1803 -1865 (Orr and Smith [etc.], 1845)

Penjing plants from China : Buxus sinica, Ehretia microphylla, Podocarpus macrophyllus, Sageretia thea, Serissa foetida - United States. Animal; Plant Health Inspection Service. Plant Protection; Quarantine Programs. Biological Assessment; Taxonomic Support. (Biological Assessment and Taxonomic Support, Plant Protection and Quarantine, Animal and Plant Health Inspection Service, U.S. Dept. of Agriculture, 1996)

Perfil botánico-geológico de la carretera México-Acapulco - Mexico Secretaria de la Economia Nacional. Oficina de Geografia Economica (Talleres Gráficos de la Nación, 1935)

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

Perú : Cerros de Kampankis - Stotz, Douglas F. (Douglas Forrester), 1956 - (The Field Museum, Environment, Culture, and Conservation, 2012)

Perú, Medio Putumayo-Algodón - Stotz, Douglas F. (Douglas Forrester), 1956 - (Field Museum of Natural History, 2016)

Perú : Tapiche-Blanco - Field Museum of Natural History. (The Field Museum, 2015)

Pest control by chemical, biological, genetic, and physical means; a symposium. Chairman: E. F. Knipling ... presented at the meeting of the American Association for the Advancement of Science, Section 0 on Agriculture, December 26-31, 1964 - Knipling, E. F. (Agricultural Research Service, U.S. Dept. of Agriculture, 1966)

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