Occasional papers of the Boston Society of Natural History - Boston Society of Natural History. (Boston Society of Natural History, 1915)

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

Oesterreichische botanische Zeitschrift (A. Skofitz, 1866)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1897)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1919)

Offer #13 : Oct. 13th, 1928 - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Herbst Brothers, 1928)

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)

Offer No. 32 : April 1st, 1929 price list - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Herbst Brothers, 1929)

Öfversigt af Kongl. Vetenskaps-akademiens forhandlingar - Kungl. Svenska vetenskapsakademien. (P. A. Norstedt & Söner, 1884)

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, 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, 1903)

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

One-hundred and ninth annual catalogue of high class seeds - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (J.M. Thorburn & Co, 1910)

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

Orchard and garden (J.T. Lovett, 1889)

Oregon Nursery Company [catalog] - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Oregon Nursery Company, 1920)

Ornamental shrubs for garden, lawn, and park planting, with an account of the origin, capabilities, and adaptations of the numerous species and varieties, native and foreign, and especially of the new and rare sorts, suited to cultivation in the United States - Davis, Lucius Daniel, 1826 - (G.P. Putnam's sons, 1899)

Ornamental shrubs for garden, lawn, and park planting, with an account of the origin, capabilities, and adaptations of the numerous species and varieties, native and foreign, and especially of the new and rare sorts, suited to cultivation in the United States - Davis, Lucius Daniel, 1826 - (Putnam, 1899)

Ornamental shrubs of the United States (hardy, cultivated) - Apgar, A. C. (Austin Craig), 1838 -1908 (American Book Company, 1910)

Ornamental shrubs of the United States, hardy, cultivated - Apgar, A. C. (Austin Craig), 1838 -1908 (American Book Co, 1910)

Ornamental trees - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Fairfax Farms Nursery, 1924)

Ornamental trees - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Fairfax Farms Nursery, 1925)

Ornamental trees and plants for home grounds and other landscape gardening, fruit trees for commercial orchards and home gardens : No. 127 price list, fall 1927-spring 1928 - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (I.E. Ilgenfritz' Sons & Co, 1927)

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

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

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1912)

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 birds of song and beauty, being a complete history of all the songbirds, flycatchers, hummingbirds, swifts, goatsuckers, woodpeckers, kingfishers, trogons, cuckoos, and parrots, of North America - Nehrling, Henry, 1853 -1929 (G. Brumder, 1893)

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, 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, 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, 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 northern shrubs and how to identify them : a handbook for the nature-lover - Keeler, Harriet L. (Harriet Louise), 1846 -1921 (Charles Scribner's Sons, 1922)

Our northern shrubs and how to identify them; a handbook for the nature-lover - Keeler, Harriet L. (Harriet Louise), 1846 -1921 (C. Scribner, 1903)

Our northern shrubs and how to identify them; a handbook for the nature-lover - Keeler, Harriet L. (Harriet Louise), 1846 -1921 (Scribner, 1903)

Our northern shrubs and how to identify them; a handbook for the nature-lover - Keeler, Harriet L. (Harriet Louise), 1846 -1921 (C. Scribner, 1912)

Our trees. A popular account of the trees in the streets and gardens of Salem, and of the native trees of Essex County, Massachusetts, with the location of trees, and historical and botanical notes - Robinson, John, 1846 -1925 (Printed by N. A. Horton and Son, 1891)

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

Outpost Nurseries - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Outpost Nurseries, 1941)

Pamphlets on forestry in Kansas (1900)

Pamphlets on forestry in Maine (1900)

Pamphlets on forestry in Maryland (1900)

Pamphlets on forestry in Michigan (1900)

Pamphlets on forestry in Minnesota (1900)

Pamphlets on forestry in Nebraska (1900)

Pamphlets on forestry in North Carolina (1900)

Pamphlets on forestry in Ohio (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, 1931)

The parasitic fungi of New Jersey - Schwarze, Carl Alois, 1886 - (New Jersey Agricultural Experiment Stations, 1917)

Parks : a manual of municipal and county parks compiled as a result of a nation-wide study of municipal and county parks conducted by the Playground and Recreation Association of America, in co-operation with the American Institute of Park Executives at the request of the National Conference on Outdoor Recreation - American Institute of Park Executives. (A.S. Barnes & Co, 1928)

Part I. Palæontology - Hall, James, 1811 -1898 (Govt. print. off, 1877)

Partial list of available native plants - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Nik-Nar, 1941)

Partial list of available native plants - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Nik-Nar, 1950)

Patologia vegetale. Fanerogame parassite, mixomiceti, bacterii, ifomiceti od eumiceti (funghi) - Voglino, Pietro. (Unione tipografico-editrice [Gia ditta Pomba e c], 1905)

Pear borer - Brooks, Fred E. (Fred Ernest), 1868 -1933 (U.S. Dept. of Agriculture, 1920)

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)

Peonies and Iris - Peterson Nursery. (Peterson Nursery)

Peonies, native wild flowers, rockery plants : autumn supplement to spring of 1928 catalog - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Frank W. Campbell, 1928)

The Pequot Nurseries : wholesale list - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Pequot Nurseries, 1952)

The perfect garden, how to keep it beautiful and fruitful, with practical hints on eonomical management and the culture of all the principal flowers, fruits, and vegetables - Wright, Walter P. (Walter Page), 1864 -1940 (J. B. Lippincott company; [etc., etc.], 1908)

Perkie plants - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Ivy Hill Forest, 1955)

Perkie plants - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Ivy Hill Forest, 1957)

Perkie plants - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Ivy Hill Forest, 1959)

Pflanzenbiologische Untersuchungen : nebst algologischen Schluszbemerkungen - Hansgirg, Antonin, 1854 -1917 (Alfred Hölder, 1904)

Die Pflanzenwelt Norwegens. Ein Beitrag zur Natur- und Culturgeschichte Nord-Europas - Schübeler, F. C. (Frederik Christian), 1815 -1892 (A.W. Brögger, 1873)

Die Pflanzenwelt Norwegens : ein Beitrag zur Natur- und Culturgeschichte Nord-Europas - Schübeler, F. C. (Frederik Christian), 1815 -1892 (1873)

Philadelphia flower & garden show - Pennsylvania Horticultural Society. (The Society, 1976)

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, 1981)

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, 1992)

Phytoneuron (Guy L. Nesom, 2012)

Phytoneuron (Guy L. Nesom, 2014)

Die Pilze Böhmens - Bubák, František, 1866 -1925 (In Commission bei F. ivna, 1908)

The Pine barrens of New Jersey : September bulletin, 1929 - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (J.M. Bassett, 1929)

Pioneer Seed House, nursery & greenhouse of the Northwest, 1883-1931 : 48th annual catalog - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Oscar H. Will & Co, 1931)

Pioneer Seed House, nursery & greenhouse of the Northwest, 1883-1929 : 46th annual catalog - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Oscar H. Will & Co, 1929)

Pioneer Seed House, nursery & greenhouse of the Northwest, 1883-1928 - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Oscar H. Will & Co, 1928)

Pioneer Seed House, Nursery and Greenhouses of the Northwest, seed corn specialists : 1883-1932, 49th annual catalog - Henry G. Gilbert Nursery; Seed Trade Catalog Collection. (Oscar H. Will & Co, 1932)

Pith-ray flecks in wood - Brown, Harry Philip, 1887 -1951 (G.P.O, 1913)

Plant health care for woody ornamentals : a professional's guide to preventing and managing environmental stresses and pests - International Society of Arboriculture. (Cooperative Extension Service, College of Agricultural, Consumer and Environmental Sciences, University of Illinois at Urbana-Champaign, 1997)