North American fauna - U.S. Fish; Wildlife Service (Fish and Wildlife Service; for sale by the Supt. of Docs., U. S. Govt. Print. Off, 1981)

North American flora - New York Botanical Garden (New York Botanical Garden, 1925)

North American flora - New York Botanical Garden (New York Botanical Garden, 1931)

North American trees : being descriptions and illustrations of the trees growing independently of cultivation in North America, north of Mexico and the West Indies - Britton, Nathaniel Lord, 1859 -1934 (H. Holt and Co, 1908)

North American trees; being descriptions and illustrations of the trees growing independently of cultivation in North America, north of Mexico and the West Indies; with the assistance of John Adolph Shafer - Britton, Nathaniel Lord, 1859 -1934 (Holt, 1908)

North American trees (exclusive of Mexico and tropical United States) A handbook designed for field use - Preston, Richard Joseph, 1905 - (Iowa State University Press, 1961)

North American trees : guide to Charles F. Millspaugh Hall - Field Museum of Natural History. (1934)

The northern hardwood forest : its composition, growth, and management - Frothingham, E. H. (Earl Hazeltine), 1880 - (U.S. Dept. of Agriculture, 1915)

Notable flowers to brighten your garden, 1935 - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Bristol Nurseries, Inc, 1935)

Notes on the distribution of Pennsylvania plants : based on specimens in the Carnegie Museum of Natural History herbarium - Carnegie Museum of Natural History (Carnegie Museum of Natural History, 1989)

Notes on the flora of western Nova Scotia, 1921 - Fernald, Merritt Lyndon, 1873 -1950 (Gray Herbarium of Harvard University, 1922)

Notizblatt des Königl. Botanischen Gartens und Museums zu Berlin - Engler, Adolf, 1844 -1930 (In Commission bei Wilhelm Engelmann, 1902)

November 1931 seed for nurserymen - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Herbst Brothers, 1931)

Novon a journal of botanical nomenclature from the Missouri Botanical Garden - Missouri Botanical Garden. (Missouri Botanical Garden, 1998)

Novon a journal of botanical nomenclature from the Missouri Botanical Garden - Missouri Botanical Garden. (Missouri Botanical Garden, 2002)

Observations on the flowering plants, ferns and fern allies growing wild in Marquette County, Michigan, in 1916 and 1917, especially in the vicinity of the Huron Mountain Club - University of Michigan. Museum of Zoology. (Published by the University, 1918)

Occasional papers of the Boston Society of Natural History - Boston Society of Natural History. (Boston Society of Natural History, 1921)

Occasional papers of the Museum of Zoology, University of Michigan - University of Michigan. Museum of Zoology. (University of Michigan, 1922)

Occasional papers of the Museum of Zoology, University of Michigan - University of Michigan. Museum of Zoology. (University of Michigan, 1921)

Offer No. 29 : February 9th, 1929 price list - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Herbst Brothers, 1929)

Offer No. 31 : March 9th, 1929 price list - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Herbst Brothers, 1929)

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, 1903)

The Ohio naturalist - Ohio Academy of Science. (Biological Club of the Ohio State University, 1904)

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, 1908)

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, 1910)

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

On the forestry conditions of northern Wisconsin - Roth, Filibert, 1858 -1925 (The State, 1898)

The Ontario natural science bulletin - Wellington Field Naturalists' Club. (Wellington Field Naturalists' Club, 1912)

The Oölogist for the student of birds, their nests and eggs - Lattin, Frank H. (Frank H. Lattin, 1915)

Opuscula philolichenum (J. Lendemer, 2009)

Opuscula philolichenum (J. Lendemer, 2015)

Opuscula philolichenum (J. Lendemer, 2016)

Opuscula philolichenum (J. Lendemer, 2017)

Opuscula philolichenum (J. Lendemer, 2018)

Opuscula philolichenum (J. Lendemer, 2020)

Orchard injury by the hickory tiger-moth - Isely, Dwight, 1887 -1974 (U.S. Dept. of Agriculture, 1918)

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)

Ornamental plants for immediate effects : autumn 1936 - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (E.C. Robbins, 1936)

Ornamental plants for immediate effects : for the autumn of 1937 - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Gardens of the Blue Ridge, 1937)

Ornamental plants for immediate effects for the autumn of 1938 - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (E.C. Robbins, 1938)

Ornamental plants for immediate effects for the spring of 1938 - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (E.C. Robbins, 1938)

Ornamental plants for immediate effects : spring 1937 - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (E.C. Robbins, 1937)

Ornamental plants for pleasing landscape effects : price list for Autumn 1939 - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (E.C. Robbins, 1939)

Ornamental plants for pleasing landscape effects : price-list for spring 1940 - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (E.C. Robbins, 1940)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1910)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1914)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1913)

Ouachita National Forest, Arkansas-Oklahoma - United States. Forest Service. Southern Region. (U.S. Govt. Print. Off, 1937)

Our native trees and how to identify them : a popular study of their habits and their peculiarities - Keeler, Harriet L. (Harriet Louise), 1846 -1921 (C. Scribner's Sons, 1900)

Our native trees and how to identify them; a popular study of their habits and their peculiarities - Keeler, Harriet L. (Harriet Louise), 1846 -1921 (C. Scribner's Sons, 1912)

Our native trees and how to identify them; a popular study of their habits and their peculiarities - Keeler, Harriet L. (Harriet Louise), 1846 -1921 (C. Scribner's Sons, 1910)

Our native trees and how to identify them; a popular study of their habits and their peculiarities - Keeler, Harriet L. (Harriet Louise), 1846 -1921 (C. Scribner's Sons, 1913)

Our native trees and how to identify them; a popular study of their habits and their peculiarities - Keeler, Harriet L. (Harriet Louise), 1846 -1921 (C. Scribner's Sons, 1917)

Our native trees and how to identify them; a popular study of their habits and their peculiarities - Keeler, Harriet L. (Harriet Louise), 1846 -1921 (Scribner, 1902)

Our trees, how to know them; photographs from nature - Weed, Clarence Moores, 1864 -1947 (Lippincott, 1936)

The oyster industry - United States. Bureau of Fisheries. (Govt. Print. Off, 1881)

Die palaeobotanische Literatur : bibliographische Übersicht über die Arbeiten aus dem Gebiete der Palaeobotanik - Jongmans, W. (Willem), 1878 -1957 (Fischer, 1913)

Pamphlets on forest protection (1900)

Pamphlets on forest utilization (1900)

Pamphlets on forestry in Maryland (1900)

Pamphlets on forestry in Massachusetts (1900)

Pamphlets on forestry in Michigan (1900)

Pamphlets on forestry in Minnesota (1900)

Pamphlets on forestry in Nebraska (1900)

Pamphlets on forestry in Pennsylvania (1900)

Pamphlets on forestry in Tennessee (1900)

Pamphlets on silviculture (1899)

The Pan-Pacific entomologist - Van Duzee, Edward P. (Edward Payson), 1861 -1940 (Pacific Coast Entomological Society, 1963)

Papers and reports upon forestry, forest schools, forest administration and management in Europe, America, and the British possessions, and upon forests as public parks and sanitary resorts - Kirkwood, Alexander, 1823 -1901 (s.n.], 1893)

Papers from the Department of forest entomology - Osborn, Herbert 1856 -1954 (1922)

Papers from the Department of Forest Entomology - New York. College of Forestry, Syracuse. Dept. of Forest Entomology. (The University, 1922)

Pennsylvania trees - Illick, Joseph S. (Joseph Simon), 1884 -1967 (W.S. Ray, State Printer, 1914)

Pennsylvania trees - Illick, Joseph S. (Joseph Simon), 1884 -1967 (W. S. Ray, State Printer, 1915)

Das Pflanzenreich :regni vegetablilis conspectus - Engler, Adolf, 1844 -1930 (W. Engelmann, 1904)

Phytogeographic survey of North America. A consideration of the phytogeography of the North American continent, including Mexico, Central America and the West Indies, together with the evolution of North American plant distribution - Harshberger, John W. (John William), 1869 -1929 (W. Engelmann, 1911)

Phytogeography of Nebraska. 1. General survey by Roscoe Pound and Frederic E. Clements - Clements, Frederic E. (Frederic Edward), 1874 -1945 (Published by the Seminar, 1900)

Phytologia - Moldenke, Harold N. (Harold Norman), 1909 -1996 (H.A. Gleason and H.N. Moldenke, 1953)

Phytologia - Moldenke, Harold N. (Harold Norman), 1909 -1996 (H.A. Gleason and H.N. Moldenke, 1961)

Phytologia - Moldenke, Harold N. (Harold Norman), 1909 -1996 (H.A. Gleason and H.N. Moldenke, 1983)

Phytologia - Moldenke, Harold N. (Harold Norman), 1909 -1996 (H.A. Gleason and H.N. Moldenke, 1984)

Phytologia - Moldenke, Harold N. (Harold Norman), 1909 -1996 (H.A. Gleason and H.N. Moldenke, 1987)

Phytologia - Moldenke, Harold N. (Harold Norman), 1909 -1996 (H.A. Gleason and H.N. Moldenke, 1989)