Öfversigt af Kongl. Vetenskaps-akademiens forhandlingar - Kungl. Svenska vetenskapsakademien. (P. A. Norstedt & Söner, 1850)

Öfversigt af Kongl. Vetenskaps-akademiens forhandlingar - Kungl. Svenska vetenskapsakademien. (P. A. Norstedt & Söner, 1854)

Öfversigt af Kongl. Vetenskaps-akademiens forhandlingar - Kungl. Svenska vetenskapsakademien. (P. A. Norstedt & Söner, 1880)

Öfversigt af Kongl. Vetenskaps-akademiens forhandlingar - Kungl. Svenska vetenskapsakademien. (P. A. Norstedt & Söner, 1883)

On molecular and microscopic science - Somerville, Mary Fairfax, 1780 -1872 (J. Murray, 1869)

On molecular and microscopic science - Somerville, Mary, 1780 -1872 (J. Murray, 1869)

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)

Open-air studies in botany : sketches of British wild flowers in their homes - Praeger, R. Lloyd (Robert Lloyd), 1865 -1953 (Griffin, 1897)

The Orchadian - Australasian Native Orchid Society (The Society, 1970)

The Orchadian - Australasian Native Orchid Society (The Society, 1976)

The Orchadian - Australasian Native Orchid Society (The Society, 1977)

The Orchadian - Australasian Native Orchid Society (The Society, 1963)

The Orchadian - Australasian Native Orchid Society (The Society, 1980)

The Orchadian - Australasian Native Orchid Society (The Society, 1978)

The Orchadian - Australasian Native Orchid Society (The Society, 1985)

The Orchadian - Australasian Native Orchid Society (The Society, 1984)

The Orchadian - Australasian Native Orchid Society (The Society, 1987)

The Orchadian - Australasian Native Orchid Society (The Society, 1989)

The Orchadian - Australasian Native Orchid Society (The Society, 1990)

The Orchadian - Australasian Native Orchid Society (The Society, 1992)

The Orchadian - Australasian Native Orchid Society (The Society, 1991)

The Orchadian - Australasian Native Orchid Society (The Society, 1995)

The Orchadian - Australasian Native Orchid Society (The Society, 1993)

The Orchadian - Australasian Native Orchid Society (The Society, 1999)

The Orchadian - Australasian Native Orchid Society (The Society, 2000)

The Orchadian - Australasian Native Orchid Society (The Society, 2004)

The Orchadian - Australasian Native Orchid Society (The Society, 2007)

The Orchadian - Australasian Native Orchid Society (The Society, 2008)

The Orchid review (Orchid Review ltd.], 1910)

The Orchid review (Orchid Review ltd.], 1917)

The Orchid review (Orchid Review ltd.], 1920)

The Orchid world. A monthly illustrated journal entirely devoted to orchidology - Wilson, Gurney, 1878 - (Alabaster, Passmore & Sons, ltd., printers], 1915)

Orchidaceae: illustrations and studies of the family Orchidaceae - Ames, Oakes, 1874 -1950 (Houghton, Mifflin, 1905)

Orchidaceae: illustrations and studies of the family Orchidaceae - Ames, Oakes, 1874 -1950 (Houghton, Mifflin, 1908)

Orchidaceae: illustrations and studies of the family Orchidaceae - Ames, Oakes, 1874 -1950 (Houghton, Mifflin, 1915)

Orchidaceae: illustrations and studies of the family Orchidaceae - Ames, Oakes, 1874 -1950 (Houghton, Mifflin, 1920)

Orchidaceae: illustrations and studies of the family Orchidaceae - Ames, Oakes, 1874 -1950 (Houghton, Mifflin, 1922)

Orchidaceele din România - Pantu, Zacharia C., 1866 -1934 (Librariile Socec & co. [etc.], 1915)

Orchidacées - Hallé, Nicolas (1977)

Les orchidées, histoire iconographique, organographie, classification, géographie, collections, commerce, emploi, culture, avec une revue descriptive des espèces cultivées en Europe; ouvrage orné de 244 vignettes et de 50 chromolithographics - Puydt, Émile de, 1810 -1891 (J. Rothschild, 1880)

Les orchidées : manuel de l'amateur - Bois, D. (Désiré), 1856 -1946 (J.-B. Baillière et fils, 1893)

Le orchidee - Pucci, Angiolo, 1851 - (U. Hoepli, 1905)

Die Orchideen :ihre Beschreibung, Kultur und Zu¨chtung. Handbuch fu¨r Orchideenliebhaber, Zu¨chter und Botaniker - Schlechter, Rudolf, 1872 -1925 (P. Parey, 1915)

Die Orchideen von Ambon - Smith, J. J. (Johannes Jacobus), 1867 -1947 (Landsdrukkerij, 1905)

Die orchideen von Java - Smith, J. J. (Johannes Jacobus), 1867 -1947 (E. J. Brill, 1905)

Les orchidées exotiques et leur culture en Europe - Cogniaux, Alfred, 1841 -1916 (l'Auteur, 1894)

Orchidophile; journal des amateurs d'orchideés - Godefroy-Lebeuf, A. (Alexandre), 1844 -1903 (1885)

Orchidophile; journal des amateurs d'orchideés - Godefroy-Lebeuf, A. (Alexandre), 1844 -1903 (1886)

Orchidophile; journal des amateurs d'orchideés - Godefroy-Lebeuf, A. (Alexandre), 1844 -1903 (1887)

Orchidophile; journal des amateurs d'orchideés - Godefroy-Lebeuf, A. (Alexandre), 1844 -1903 (1891)

Orchids; being the report on the Orchid Conference held at South Kensington (Macmillan & Co, 1886)

The orchids in the Ottawa District : floristics, phytogeography, population studies and historical review / Joyce M. Reddoch and Allan H. Reddoch - Ottawa Field-Naturalists' Club (The Ottawa Field-Naturalists' Club, 1997)

Orchids of Lakeland : a field guide to Lakeland Provincial Park, Provincial Recreation Area and surrounding region - Alberta. Alberta Environmental Protection. (Alberta Environmental Protection, 1998)

The orchids of New England; a popular monograph - Baldwin, Henry, 1846 -1911 (J. Wiley, 1884)

The orchids of New England. A popular monograph - Baldwin, Henry, 1846 -1911 (J. Wiley & Sons, 1884)

Orchids of Panama : a facsimile reprint of the Orchidaceae, Flora of Panama - Williams, Louis O. 1908 -1991 (Missouri Botanical Garden, 1980)

Orchis :Monatsschrift der Deutschen Gesellschaft für Orchideenkunde - Dammer, Udo. (1910)

Orchis :Monatsschrift der Deutschen Gesellschaft für Orchideenkunde - Dammer, Udo. (1919)

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, 1971)

Otia botanica Hamburgensia :Fasciculus primus [-secundus, pars prima] - Reichenbach, H. G. (Heinrich Gustav) 1824 -1889 (Typis T. T. Meissneri, 1878)

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

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

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1883)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1888)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1889)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1907)

Papers on pollination - Darwin, Charles, 1809 -1882 (1861)

Paxton's magazine of botany, and register of flowering plants - Paxton, Joseph, Sir, 1803 -1865 (Orr and Smith [etc.], 1836)

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 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)