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, 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, 1913)

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

Optimal sites for seedlings of ten conifers - University of Alberta. Dept. of Agricultural Engineering. (1977)

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 spring 1940 - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (E.C. Robbins, 1940)

Ornamental trees, shrubs, and woody climbers - Macoun, W. T. (William Tyrrell), 1869 -1933 (Canada Dept. of Agriculture, 1927)

The Orthoptera of Indiana : an illustrated descriptive catalogue of the species known to occur in the state, with bibliography, synonymy and descriptions of new species - Blatchley, W. S. (Willis Stanley), 1859 -1940 ([Indiana Dept. of Geology and Natural Resources, 1903)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1909)

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

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 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, 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, 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, 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, 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 (McClelland, Goodchild & Stewart, 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 (Scribner, 1902)

Pamphlets on forest protection (1900)

Pamphlets on forestry (1900)

Pamphlets on forestry. History (1900)

Pamphlets on forestry in Japan (1900)

Pamphlets on forestry in Maine (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 North Dakota and South Dakota (1900)

Pamphlets on forestry in Pennsylvania (1900)

Pamphlets on silviculture (1899)

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)

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)

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)

Permanent sample plot (psp) field procedures manual - Alberta. Alberta Sustainable Resource Development. (Alberta Sustainable Resource Development, Public Lands and Forests Division, Forest Management Branch, 2005)

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

Phytogeographic studies in the Peace and upper Liard river regions, Canada, with a catalogue of the vascular plants - Raup, Hugh M. (Hugh Miller), 1901 -1995 (Arnold Arboretum of Harvard university, 1934)

Phytologia - Moldenke, Harold N. (Harold Norman), 1909 -1996 (H.A. Gleason and H.N. Moldenke, 1967)

Phytoneuron (Guy L. Nesom, 2015)

Pinophyta (Gymnosperms) of New York State - Cope, Edward A., 1948 - (University of the State of New York, the State Education Dept, 1990)

The pinus contorta vegetation of Banff and Jasper National Parks - University of Alberta. Department of Botany. (University of Alberta, 1969)

Plant biomass in the Tanana River basin, Alaska - Pacific Northwest Research Station (Portland, Or.) (U.S. Dept. of Agriculture, Forest Service, Pacific Northwest Research Station, 1995)

Plant community types of sand dunes and sand plains in selected areas of the boreal natural region - Alberta. Alberta Sustainable Resource Development. (The Company, 2005)

Plant ecology - McDougall, W. B. (Walter Byron), 1883 - (Lea & Febiger, 1941)

Plant hardiness zone map - American Horticultural Society. (Agricultural Research Service, 1965)

The plant life of Maryland - Shreve, Forrest, 1878 -1950 (Johns Hopkins Press, 1910)

Plant list of Waterloo County - Montgomery, F. H. (Frederick Howard), 1902 - (1943)

Plant materials of decorative gardening; the woody plants - Trelease, William, 1857 -1945 (The author, 1921)

Plant materials of decorative gardening; the woody plants - Trelease, William, 1857 -1945 (The author, 1917)

The Plant world - Plant World Association. (Plant World Association [etc.], 1908)

The Plant world - Plant World Association. (Plant World Association [etc.], 1909)

The Plant world - Plant World Association. (Plant World Association [etc.], 1912)

The Plant world - Plant World Association. (Plant World Association [etc.], 1917)

The Plant world - Plant World Association. (Plant World Association [etc.], 1918)

Plants & gardens - Brooklyn Botanic Garden. (Brooklyn Botanic Garden, 1946)

Plants & gardens - Brooklyn Botanic Garden. (Brooklyn Botanic Garden, 1969)

Plants & gardens - Brooklyn Botanic Garden. (Brooklyn Botanic Garden, 1984)

Plants of James' Bay collected by David Potter - Potter, David, 1894 -1967 (1929)

Plants of Labrador and Baffin Land coll. C.S. Sewall, 1927-'28 - Sewall, Charles Summers, 1875 -1957 (1927)

The plants of Michigan; simple keys for the identification of the native seed plants of the state - Gleason, Henry A. (Henry Allan), 1882 -1975 (G. Wahr, 1918)

The plants of Prince Edward Island - Erskine, D. S. (David Sterling) (Research Branch, Agriculture Canada, 1985)

The plants of Prince Edward Island - Erskine, D. S. (David Sterling) (Plant Research Institute, Research Branch, Canada Dept. of Agriculture, 1960)

The plants of Prospect Park - Jelliffe, Smith Ely, 1866 -1945 (1890)

Plants of Riding Mountain National Park, Manitoba - Canadian Parks Service. (Research Branch, Agriculture Canada, 1988)

Plants of the U.S. Military Academy, West Point, New York - Barringer, Kerry Alan (Brooklyn Botanic Garden, 1990)

The Polyporaceae of Wisconsin - Neuman, Julius John. (The State, 1914)