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- Tester, Patricia A.
- Testerman, John K
- Testo, Weston L
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- Testut, L. (Léo), 1849-1925
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- Tetali, P.
- Tetali, Sujata
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- Tetens Nielsen, Astrid
- Tetens Nielsen, Erik
- Tetens, H.
- Tetenyi, Peter
- Teter, Harold E.,
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- Tether & Don (Firm)
- Tether Seed Co.
- Tether, Rob B.
- Tetirick, J. Willis.
- Tetley Nurseries.
- Tetley, M. I.
- Tetley, Richard.
- Tetlie, Odd Erik
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- Teton County Conservation District.
- Tetra Tech, inc.
- Tetrault, Kim
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- Tétry, Andrée, 1907-1992
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- Tetsuo, Harada
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- Teubner, B. G. (Benediktus Gotthelf), 1784-1856
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- Texas A & M University
- Texas A & M University. Dept. of Oceanography.
- Texas A. and M. Research Foundation.
- Texas Academy of Science.
- Texas Agricultural Experiment Station.
- Texas Cactus and Novelty Company.
- Texas Christian University.
- Texas Forest Service.
- Texas Medical Center.
- Texas Nursery Company (Sherman, Tex.)
- Texas Ornithological Society.
- Texas Pecan Nursery.
- Texas Research Foundation (Renner)
- Texas Rose Farms.
- Texas Rose Garden.
- Texas Seed & Plant Co.
- Texas Seed and Floral Co.
- Texas Seed and Floral Company.
- Texas Seed Breeding Farms.
- Texas Seed House.
- Texas Seed Pecan Co.
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- Texas Tech University. Museum,
- Texas Tech University. Natural Science Research Laboratory.
- Texas.
- Texas. Dept. of Agriculture, Insurance, Statistics and History.
- Texas. Dept. of education.
- Texas. Fish and oyster commissioner.
- Texas. Game, Fish, and Oyster Commission.
- Texas. Parks and Wildlife Department.
- Texas. State Board for Vocational Education.
- Texas. State Seed and Plant Board,
- Texeira, R. H. F.
- Texidor y Cos, Juan
- Teyke, Thomas
- Teylers Museum.
- Teyler's Stichting, Haarlem. Bibliotheek
- Teyler's Stichting, Haarlem. Museum. Bibliotheek
- Teysmann, Johannes Elias, 1808-1882
- Tezcan, Serdar
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- TGS Technology, Inc.
- Th. F. Van der Meulen (Firm)
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- Thabes, John.
- Thacer, George Blake, 1906-
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- Thananthaisong, Theerawat
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- Thawatchai, Santisuk
- Thaweesakdi Boonkerd.
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- Thaxter, Mabel
- Thaxter, Roland, 1858-1932
- Thayer Fruit Farms.
- Thayer, Abbott Handerson, 1849-1921
- Thayer, C. C.
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- Thayer, E. F.
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- The Globe
- The Hamilton Bird Protection Society Inc
- The Harmony Nursery,
- The Merrys,
- The Nature Conservancy.
- The New York Times
- The Ortonville Nurseries,
- The Pinto Tag Nursery,
- The Republican
- The Roberts Rose Company
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