- Ulke, Henry
- Ulke, Titus
- Ulla, M. Shafaat
- Ullah, Misbah
- Ullah, Zahid
- Ullah, Zia
- Ullathorne Seed Co.
- Ullenbruch, Klaus
- Ullepitsch, Josef
- Ullholm, Jonas
- Ullman, L. (Ludwig).
- Ullmann, Albert Thomas
- Ullmann, Judith
- Ulloa Ulloa, Carmen, 1963-
- Ulloa, Andres
- Ulloa, Antonio de, 1716-1795
- Ulloa, Erica
- Ulloa, Héctor
- Ulloa, Jorge
- Ulloa, José
- Ulloa, Luis
- Ulloa, Mauricio
- Ulloa, Miguel
- Ulloa, Osvaldo
- Ulloa, Patricio
- Ulloa, Raúl
- Ulloa, Wilson
- Ulloa-Montemayor, Ximena
- Ulloa-Rubio, Karla A.
- Ullrich, Alexander
- Ullrich, Bernd
- Ullrich, Hans, 1913-2002
- Ullrich, James R.
- Ullyett, Henry.
- Ullyette Brothers.
- Ullyette, C. L.
- Ullyette, William.
- Ulman, Aylin
- Ulman, P. T.
- Ulmen, Karin
- Ulmer, Georg, 1877-1963
- Ulmer, Jonah M.
- Ulmer, Kevin M
- Ulmer, Torsten
- Ulrey, Ivon W. (Ivon William), 1908-
- Ulrich Nursery.
- Ulrich, August
- Ulrich, E. O. (Edward Oscar), 1857-1944
- Ulrich, Gary W.
- Ulrich, George H. F. (George Henry Frederick), 1830-1900
- Ulrich, Hans
- Ulrich, James R.
- Ulrich, John Linck, 1877-
- Ulrich, Maria Danuta.
- Ulrich, Rainer
- Ulrich, Sterling
- Ulrich, Wilhelm.
- Ultsch, Gordon R.
- Ultsch, Gordon Richard, 1942-
- Uludag, Ahmet
- Ulukapı, Merve
- Ulukuş, Deniz
- Ulusoy, Fatma
- Ulysséa, Mônica Antunes
- Ulziimaa, Gombosuren
- Um Nyobe, Philène Corine Aude
- UMA Engineering Ltd.
- Uma, Eswaranpillai
- Umadilla Nurseries.
- Umali-Garcia, Mercedes, 1936-
- Umamaheswari, P.
- Umamaheswari, U.
- Umaña Dodero, Gina
- Umaña, César Leandro Abozaglo
- Umaña, Fernando
- Umaña, María Natalia
- Umaña-Villalobos, Gerardo
- Umanets, Olha
- Umapathy, G.
- Umar, Aisha
- Umaran, Ángel
- UMass Extension.
- Umbach, Levi Menger, 1853-1918
- Umbrasko, Inta
- Umeda, Masaki
- Umemura, Yoshihiro
- Umenoya, Tsuruko, 1802-1864
- Umesh, Divya
- Umetsu, Fabiana
- Umminger, Bruce L
- Ummul-Nazrah, A. R.
- Umoh, U. O.
- Umphelby, Fanny, 1788-1852
- Umpleby, John H.
- Umpunjun, Puangpaka
- Una A F
- Unadilla Nurseries.
- Unadilla Nursery Company.
- Unadilla Nursery Gardens.
- Unal, Mustafa
- Unal, Sevgi
- Unamuno e Irigoyen, Luis Mariano
- Unbekannt
- UNC Sea Grant College Program.
- Uncas Dahlia Farm.
- Unda-Harp, Karime
- Undaharta, Ni Kadek Erosi
- Underbakke, Larry D.
- Underhill, Benjamin Mott.
- Underhill, Elizabeth M.
- Underhill, Frank P. (Frank Pell), 1877-1932
- Underhill, George D.
- Underhill, George F.
- Underhill, J. Edward
- Underhill, James C
- Underhill, L. C.
- Underhill, Leslie G.
- Underhill, Lora A.
- Undersea Science Symposium National Undersea Research Center) 1987-
- Underwood Farms.
- Underwood, Angus
- Underwood, Antony J
- Underwood, Antony, J
- Underwood, Avril H
- Underwood, Benjamin A
- Underwood, C F
- Underwood, Cecil F., 1867-1943
- Underwood, Cecilio F.
- Underwood, Charles J.
- Underwood, Dessie L. A.
- Underwood, Emma C
- Underwood, Garth
- Underwood, Graham J. C.
- Underwood, H. G.
- Underwood, Jay Gove, 1873-
- Underwood, Judson Kemp, 1898-1975
- Underwood, Loring, 1874-1930
- Underwood, Lucien Marcus, 1853-1907
- Underwood, Review By: L M
- Underwood, Review By: Lucien M
- Underwood, Robert
- Underwood, Robyn M.
- Underwood, Todd J.
- Underwood, Wm. Lyman, 1864-1929
- Underwood.
- Undlin, Kent.
- Undrits, G. F. (German Frantsevich), 1874
- UNEP World Conservation Monitoring Centre.
- Unesco.
- Unfer, Taís Cristina
- Ungar, Irwin A.
- Ungaretti, Ieti
- Ungaro, Nicola
- Ungemach, Louis F.
- Unger Brothers (Berlin, Germany),
- Unger, F. (Franz), 1800-1870
- Unger, Frederic William, 1875-
- Unger, Jacob.
- Unger, Johann Friedrich.
- Unger, Johann Gottfried, 1706-1771
- Unger, K.
- Unger, Manuela
- Ungerer, Emil, 1888-
- Ungerer, Natasha K.
- Ungerfeld, Rodolfo
- Ungricht, Stefan
- Union Bulb Co., Mount Clemens, Michigan
- Union catholique de Montréal.
- Union catholique des scientifiques français.
- Union Coloniale Française, Paris.
- Union County Nurseries.
- Union entomologique.
- Union Fork and Hoe Co.
- Union Nurseries (Los Angeles, Calif.)
- Union Nurseries (Union, Or.)
- Union Nurseries.
- Union Nursery.
- Union Orchard and Nursery Company.
- Union Pacific Railroad Company.
- Union Pacific Railroad Company. Passenger Dept.
- Union Pacific railway company.
- Union Plant Co.
- Union Plant Co. Inc.
- Union Plant Company.
- Union Seed & Fuel Company.
- Union Theological Seminary (New York, N.Y.)
- Unione Degli Scienziati Italiani Lucca, Italy) 1843-
- Unione malacologica italiana.
- Unione zoologica italiana.
- United Bulb Company,
- United Bulb Company.
- United Bulb Growers.
- United cavy breeders association, inc.
- United fruit company.
- United Nations Conference on Science and Technology for Development Vienna, Austria) 1979-
- United Nations Department of Economic and Social Affairs, Contributions from: M. Walpole
- United Nations Framework Convention On Climate Change (Organization)
- United Nations. Environment Programme.
- United Nations. Environmental Management Group.
- United Nations. Environmental Programme. Division of Environmental Conventions.
- United ornithologists of Maine.
- United Provinces of Agra and Oudh (India). Department of Agriculture and Commerce.
- United Provinces of Agra and Oudh (India). Department of Land Records and Agriculture.
- United Provinces of Agra and Oudh (India). Dept. of Agriculture and Commerce.
- United Provinces of Agra and Oudh (India). Dept. of Land Records and Agriculture.
- United Provinces Of The Netherlands. Staten Generaal.
- United States Agricultural Society.
- United States Animal Health Association.
- United States Antarctic Research Program.
- United States Armed Forces Institute.
- United States Board on Geographic Names.
- United States Botanic Garden
- United States Boys' Working Reserve.
- United States Cartridge Company.
- United States Coast Survey.
- United States Commission to the Columbian Historical Exposition at Madrid
- United States Employment Service
- United States Entomological Commission.
- United States Exotic Nurseries.
- United States Exploring Expedition 1838-1842
- United States Fish Commission.
- United States Geographic Board
- United States Geological Exploration of the Fortieth Parallel 1867-1881
- United States Military Academy. Department of Tactics.
- United States National Museum
- United States National Museum. Division of Vertebrate Paleontology.
- United States Naval Astronomical Expedition 1849-1852
- United States Naval Astronomical Expedition, 1849-1852.
- United States Naval Lyceum.
- United States Naval Observatory.
- United States North Pacific Exploring Expedition (1853-1856)
- United States Nurseries.
- United States Nursery Co.
- United States Nursery Co. (San Antonio, Tex.)
- United States Postal Service
- United States Railroad Administration.
- United States Salvage Association.
- United States Seed Co.,
- United States Tropical Nurseries.
- United States Trotting Association.
- United States Veterinary Medical Association.
- United States.
- United States. Adjutant-General's Office. Military Information Division.
- United States. Agency for International Development.
- United States. Bureau of Land Management. Desert Planning Staff-
- United States. Department of Agriculture.
- United States. National Park Service. Denver Service Center.
- United States. Public Health and Marine Hospital Service.
- United States.: Bureau of Entomology
- United States.: Bureau of Entomology and Plant Quarantine