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

Organologisches, systematisches und Arten-Register zu den Tafeln des Handbuch's der botanischen Terminologie - Bischoff, Gottlieb Wilhelm, 1797 -1854 (J.L. Schrag, 1849)

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)

The origin of life and process of reproduction in plants and animals : with the anatomy and physiology of the human generative system, male and female, and the causes, prevention and cure of the special diseases to which it is liable : a plain, practical treatise, for popular use - Hollick, Frederick, 1818 -1900 (David McKay, 1902)

L'origine et le développement des flores dans le massif central de France; avec aperçu sur les migrations des flores dans l'Europe sud-occidentale - Braun-Blanquet, J. (Josias), 1884 -1980 (L. Lhomme, 1923)

Florist's journal (How and Parsons, 1844)

Ornithologisches Jahrbuch (V. Tschusi, 1904)

The Osprey (The Osprey Co, 1898)

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

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1889)

Our living resources : a report to the nation on the distribution, abundance, and health of U.S. plants, animals, and ecosystems - United States. National Biological Service. (U.S. Dept. of the Interior, National Biological Service, 1995)

Our wild flowers - Jack, I. Allen (Isaac Allen), 1843 -1903 (s.n.], 1896)

Outdoor studies. Poems - Higginson, Thomas Wentworth, 1823 -1911 (Houghton, Mifflin and company, 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)

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

Outlines of plant life : with special reference to form and function - Barnes, Charles Reid, 1858 -1910 (Henry Holt and Company, 1900)

Outlines of the natural history of Great Britain and Ireland, containing a systematic arrangement and concise description of all the animals, vegetables and fossiles which have hitherto been discovered in these kingdoms - Berkenhout, John, 1730 -1791 (Printed for P. Elmsly (Successor to Mr. Vaillant), 1770)

Over de bevruchting der bloemen in het kempisch gedeelte van Vlaanderen - MacLeod, Julius, 1857 -1919 (Vuylsteke, 1894)

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)

Une page d'histoire de la medecine : la thérapeutique sous les premiers Césars - Lépine, R. (Raphael), 1840 -1919 (F. Alcan, 1890)

Palaeontographica (Theodor Fischer, 1855)

Palaeontographica (Theodor Fischer, 1859)

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

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1886)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1892)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1900)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1904)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1916)

Papers presented at the Celebration of the Twentieth Anniversary of the New York Botanical Garden, September 6-9, 1915. Published by the aid of the David Lydig Fund, bequethed by Charles P. Daly - New York Botanical Garden (1916)

Park and cemetery - Haight, R. J. (Rufus J.) (R.J. Haight, 1900)

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

Patterson's numbered check-list of North American plants north of Mexico - Patterson, Harry N. (Harry Norton), 1853 -1919 (Patterson, 1892)

Paxton's Botanical dictionary; comprising the names, history, and culture of all plants known in Britain; with a full explanation of technical terms. New ed. including all the new plants up to the present year - Paxton, Joseph, Sir, 1803 -1865 (Bradbury, Evans, & co, 1868)

Paxton's flower garden - Lindley, John, 1799 -1865 (Cassell, Petter, Galpin & Co, 1883)

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

Pestmegye és tájéka viránya - Gönczy, Pál, 1817 -1892 (Magyar Királyi Egyetemi Nyomda Sajátja, 1879)

Pestmegye és tájéka viránya - Gönczy, Pál, 1817 -1892 (Ráth mór Bizománya, 1864)

Peter D. Knieskern and John Torrey correspondence, 1836-1858 - Knieskern, Peter D., 1798 -1871 (1839)

Peter Parley's cyclopedia of botany : including familiar descriptions of trees, shrubs and plants - Parley, Peter. (Otis, Broaders and Co, 1838)

Petite flore de Belgique à l'usage des écoles - Cogniaux, Alfred, 1841 -1916 (Hector Manceaux, 1883)

Petite flore de la Mayenne - Léveillé, H. (Hector), 1863 -1918 (Goupil, 1895)

Petro nomine ac imperio primo Brasiliensis imperii perpetuo defensore ... jubente Florae fluminensis icones, nunc primo eduntur ... - Velloso, José Mariano da Conceição, 1742 -1811 (Ex off. lithogr. Senefelder, curante J. Knecht, 1827)

Pets and how to care for them - Crandall, Lee S. (Lee Saunders), 1887 -1969 (New York zoological park, 1921)

Pets; their history and care - Crandall, Lee S. (Lee Saunders), 1887 -1969 (H. Holt and company, 1917)

Pets : their history and care. With illus. from life - Crandall, Lee S. (Lee Saunders), 1887 -1969 (Holt, 1917)

P.F. Cürie's Anleitung, die im mittleren und nördlichen Deutschland wildwachsenden und angebauten Pflanzen auf eine leichte und sichere Weise durch eigene Untersuchung zu bestimmen - Cürie, P. F. (C.G. Zobel, 1856)

Pflanzen-geographie auf physiologischer Grundlage - Schimper, A. F. W. (Andreas Franz Wilhelm), 1856 -1901 (Gustav Fischer, 1908)

Pflanzen-teratologie systematisch geordnet - Penzig, O. (Ottone), 1856 -1929 (A. Ciminago, 1894)

Pflanzenbiologische Schilderungen - Goebel, K. (Karl), 1855 -1932 (N.G. Elwert, 1889)

Pflanzenbiologische Schilderungen - Goebel, K. (Karl), 1855 -1932 (N.G. Elwert, 1891)

Pflanzenbiologische Studien - Lundström, Axel Nikolaus, 1847 -1905 (Druck der Akademischen Buchdruckerei, Edv. Berling, 1884)

Die Pflanzendecke der Erde : populäre Darstellung der Pflanzengeographie für gebildete Naturfreunde - Rudolph, Ludwig, 1813 -1896 (Nicolaische Verlagsbuchhandlung, 1859)

Die Pflanzendecke Österreich-Ungarns. Auf Grund fremder und eigener Forschungen geschildert - Hayek, August von, 1871 -1928 (F. Deuticke, 1914)

Die Pflanzenfeinde aus der Klasse der Insekten. Ein nach Pflanzenfamilien geordnetes Handbuch sämmtlicher auf den einheimischen Pflanzen bisher beobachteten Insekten zum Gebrauch für Entomologen, Insektensammler, Botaniker, Land- und Forstwirthe und Gartenfreunde - Kaltenbach, J. H. (Johann Heinrich), 1807 -1876 (J. Hoffmann, 1874)

Das Pflanzenleben der Schweiz - Christ, H. (Hermann), 1833 -1933 (F. Schulhess, 1882)

Pflanzenphysiologie als Theorie der Gärtnerei. Für Botaniker, Gärtner, Landwirte, Forstleute und Pflanzenfreunde - Molisch, Hans, 1856 -1937 (G. Fischer, 1922)

Pflanzenphysiologie; ein Handbuch der Lehre vom Stoffwechsels und Kraftwechsels in der Pflanze - Pfeffer, W. (Wilhelm), 1845 -1920 (W. Engelmann, 1897)

Pflanzenphysiologie; ein Handbuch der Lehre vom Stoffwechsel und Kraftwechsel in der Pflanze - Pfeffer, W. (Wilhelm), 1845 -1920 (W. Engelmann, 1897)

Pflanzenphysiologie; Versuche und Beobachtungen an böheren und niederen Pflanzen einschliesslich Bakteriologie und Hydrobiologie mit Planktonkunde - Kolkwitz, R. (Richard), 1873 -1956 (G. Fischer, 1922)