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Preliminary list of the plants growing without cultivation in Alabama - Mohr, Charles (Charles Theodore), 1824 -1901 (1880)

A preliminary list of the vascular flora of Allegheny County, Pennsylvania - Shafer, John Adolph, 1863 -1918 (Carnegie Institute Museum?, 1901)

A preliminary list of the vascular plants of the Lackawanna and Wyoming valleys - Dudley, William Russel, 1849 -1911 (The Republican Press, 1887)

A preliminary report on the biology of Harding County, northwestern South Dakota - Visher, Stephen Sargent, 1887 -1967 (State Publishing Co, 1914)

A preliminary verified list of plant collectors in Mexico - Knobloch, Irving W. (Irving William), 1907 - (Harold N. Moldenke and Alma L. Moldenke, 1983)

Principia botanica: or, A concise and easy introduction to the sexual botany of Linnaeus ... Arranged in a tabular form, under each class and order; and digested alphabetically under several generic distinctions. Together with three indexes ... Also a table of several vegetable drugs not in the indexes ... - Darwin, Robert Waring, 1724 -1816 (Printed and sold by M. Hage; [etc., etc.], 1810)

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Proceedings of the Biological Society of Washington - Smithsonian Institution (Biological Society of Washington, 1901)

Proceedings of the Biological Society of Washington - Smithsonian Institution (Biological Society of Washington, 1917)

Proceedings of the Biological Society of Washington - Smithsonian Institution (Biological Society of Washington, 1932)

Proceedings of the Biological Society of Washington - Smithsonian Institution (Biological Society of Washington, 1935)

Proceedings of the Biological Society of Washington - Smithsonian Institution (Biological Society of Washington, 1936)

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Proceedings of the California Academy of Sciences - California Academy of Sciences (California Academy of Sciences, 1893)

Proceedings of the California Academy of Sciences. 3rd ser., Botany - California Academy of Sciences (The Academy, 1897)

Proceedings of the California Academy of Sciences, 4th series - California Academy of Sciences (California Academy of Sciences, 1923)

Proceedings of the California Academy of Sciences, 4th series - California Academy of Sciences (California Academy of Sciences, 1924)

Proceedings of the California Academy of Sciences, 4th series - California Academy of Sciences (California Academy of Sciences, 1926)

Proceedings of the California Academy of Sciences, 4th series - California Academy of Sciences (California Academy of Sciences, 1927)

Proceedings of the California Academy of Sciences, 4th series - California Academy of Sciences (California Academy of Sciences, 1943)

Proceedings of the California Academy of Sciences, 4th series - California Academy of Sciences (California Academy of Sciences, 1944)

Proceedings of the California Academy of Sciences, 4th series - California Academy of Sciences (California Academy of Sciences, 1968)

Proceedings of the California Academy of Sciences, 4th series - California Academy of Sciences (California Academy of Sciences, 2016)

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Proceedings of the Entomological Society of Washington - Entomological Society of Washington (Entomological Society of Washington, 1980)

Proceedings of the Entomological Society of Washington - Entomological Society of Washington (Entomological Society of Washington, 1993)

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Proceedings of the Indiana Academy of Science - Indiana Academy of Science. ([s.n.], 1900)

Proceedings of the Indiana Academy of Science - Indiana Academy of Science. ([s.n.], 1908)

Proceedings of the Indiana Academy of Science - Indiana Academy of Science. ([s.n.], 1911)

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The Proceedings of the Iowa Academy of Science - Iowa Academy of Science (The Academy, 1894)

The Proceedings of the Iowa Academy of Science - Iowa Academy of Science (The Academy, 1895)

The Proceedings of the Iowa Academy of Science - Iowa Academy of Science (The Academy, 1899)

The Proceedings of the Iowa Academy of Science - Iowa Academy of Science (The Academy, 1901)

The Proceedings of the Iowa Academy of Science - Iowa Academy of Science (The Academy, 1903)

The Proceedings of the Iowa Academy of Science - Iowa Academy of Science (The Academy, 1905)

The Proceedings of the Iowa Academy of Science - Iowa Academy of Science (The Academy, 1906)

The Proceedings of the Iowa Academy of Science - Iowa Academy of Science (The Academy, 1913)

The Proceedings of the Iowa Academy of Science - Iowa Academy of Science (The Academy, 1914)

The Proceedings of the Iowa Academy of Science - Iowa Academy of Science (The Academy, 1915)