Oak - 6 clippings

Oats - 2 clippings

Ochroma - 12 clippings, including Boston Traveler 1942 "Balsa is Vital to War Effort."

Ocimum - 4 clippings, including The Agricultural News 1904 "A Victim of the Mosquito Plant."

Oenothera - 4 clippings

Oil Seeds - 15 items

Oils 1.1 (up to 1910s) - 19 clippings, including American Food Journal 1912 "The Shea Butter of Africa."

Oils 1.2 (1910s) - 16 clippings, including U.S. Commerce Reports 1918 "New Oil Seed from the Kongo."

Oils 1.3 (1910s) - 6 items, including Scientific American 1919 "Using Vegetable Seeds."

Oils 2.1 (1920s - 1930s) - 21 clippings

Oils 2.2 (1920s - 1930s) - 28 clippings, including Boston Evening Transcript 1936 "Germ-Killing Oil Distilled from Australian Tree."

Oils 3 (1940s - 1950s) - 14 items

Oils 3.2 - 8 items

Okra - 2 items

Olea - 15 clippings, including Smithsonian 1985 "One of Nature's Greatest Gifts to Man."

Olearia - 4 clippings

Onion - 11 items, including Boston Traveler 1939 "Onions, Garlic and Horse Radish Seen Potential Deadly Enemies of Disease."

Opium 1 (up to 1920s) - 10 items, including The Boston Globe 1928 "Customs men seize $1,000,000 in Opium."

Opium 2 (1930s-1940s) - 13 items, including The Boston Sunday Post 1936 "Opium Ban Cost 25 Millions."

Opium 3 (1950) - 1 item

Opium 4 (1960's - 1980's) - 22 clippings, including Orientations 1979 "Old China's Opium Boxes," High Times 1982 "Master Addicts."

Opuntia - 10 clippings, including The Garden Magazine 1908 "The Oldest Flowers in Cultivation."

Oral Hygiene - 1 clipping

Oranges - 32 clippings, including Scientific American Monthly 1921 "The Perfume of the Orange."

Orchids - 19 items, including The New York Times 1972 "Orchids are Tested as Contraceptive."

Ordeal Poison - 1 clipping

Oreodoxa - 2 clippings

Ornamental Plants - 9 items

Ornamental Seeds - 2 clippings

Oroxylon - 1 clipping

Orthostemon - 3 clippings

Ostrya - 2 clippings

Oxalis - 3 items