- Claramunt-López, Bernat
- Clardy, Todd
- Clare, M R
- Clare, Shari L.
- Clarelen Orchids (Madison, Wis.)
- Clarelen Orchids, Inc. (Madison, Wis.),
- Claremont Nurseries.
- Claremont, C A
- Claremont, R M
- Clarence Aldrich (Firm)
- Clarence B. Fargo (Firm)
- Clarence E. Pine (Firm)
- Clarence H. Fogg (Firm)
- Clarence M. Kilian (Firm),
- Clarence Maban
- Clarence P. Connell
- Clarence S. Hearn Nursery.
- Clarence W. Hubbard (Firm)
- Clarence W. Hubbard (Nursery)
- Clarence Wedge (Firm)
- Clarendon Gardens Nursery,
- Clarendon Nursery Co.
- Clarendon Nursery Company.
- Clarendon Nursery.
- Clarhe, W Eagle
- Clarice Nye (Nursery)
- Clarici, Paolo Bartolomeo, 1664-1724
- Claridge, Andrew W.
- Claridge, Brandon
- Claridge, Edward
- Clarinda Nurseries.
- Clarindo, Wellington
- Claringbull, G F
- Clarinval, Colonel
- Clark Fork River Basin Project (Mont.)
- Clark Gardens (Pasadena, Calif.)
- Clark Gardner Nurseries.
- Clark Hewett (Firm)
- Clark Plant Company.
- Clark the Florist.
- Clark, A.
- Clark, A. Howard (Alonzo Howard), 1850-1918
- Clark, A. L.
- Clark, A. M.
- Clark, A. P.
- Clark, Aaron L.
- Clark, Agnes E.
- Clark, Ailsa McGown, 1926-2014
- Clark, Albertus N.
- Clark, Alice G
- Clark, Alisa Mcgown
- Clark, Alt. F.
- Clark, Amy M.
- Clark, Andrew, approximately 1678
- Clark, Anna
- Clark, Arnold C.
- Clark, Arnold M., 1916-2003
- Clark, Arthur H
- Clark, Arthur Lincoln.
- Clark, Arthur R
- Clark, Arthur.
- Clark, Austin Hobart, 1880-1954
- Clark, B.
- Clark, Benjamin Preston, 1860-1939
- Clark, Bertha May, 1880-
- Clark, Bevan
- Clark, Bonnie L
- Clark, Bracy, 1771-1860
- Clark, Brian L F
- Clark, Bruce L. (Bruce Lawrence), 1880-
- Clark, C. F. (Charles Frederick), 1873-
- Clark, C. S.
- Clark, C. S., Jr.
- Clark, Carolyn A
- Clark, Charles A.
- Clark, Charles Frederick, 1873-
- Clark, Charles H. (Charles Henry), 1887-
- Clark, Charles H. (Charles Herbert), 1854-
- Clark, Charles Hopkins
- Clark, Charles Upson.
- Clark, Christine M
- Clark, Clarence F
- Clark, Cline & Evans.
- Clark, Curtis
- Clark, D.
- Clark, D. A.
- Clark, D. P.
- Clark, Dallas L.
- Clark, Dan.
- Clark, Daniel, 1835-1912
- Clark, David B
- Clark, David L
- Clark, Deborah A
- Clark, Denise R.
- Clark, Donald
- Clark, Douglas
- Clark, Dustin
- Clark, E J
- Clark, Earl F.
- Clark, Ed H.
- Clark, Edgar W., 1922-
- Clark, Edward B. (Edward Brayton), 1860-
- Clark, Edward, 1822-1902
- Clark, Elias Treat, 1886-
- Clark, Elizabeth Hodges, 1855-1932
- Clark, Elizabeth R
- Clark, Ellen, 1915-1988
- Clark, Ellery H
- Clark, Ernest D
- Clark, Ernest Dunbar, 1886-
- Clark, Ernest Ellis, 1869-
- Clark, Esther Fraser.
- Clark, Eugenie, 1922-2015
- Clark, Everett
- Clark, F. Le Gros (Frederick Le Gros), 1892-1977
- Clark, Frances J. (Frances Janes)
- Clark, Frances L. S.
- Clark, Francis E. (Francis Edward), 1851-1927
- Clark, Frank N.
- Clark, Frederick Noad
- Clark, G. A.
- Clark, G. Herbert.
- Clark, Galen, 1814-
- Clark, Geoff
- Clark, Geoffrey
- Clark, George A. (George Archibald), 1864-1918
- Clark, George A., Jr.
- Clark, George H. (George Harold), 1872-1935
- Clark, George Huntington.
- Clark, George L. (George Lindenberg), 1892-
- Clark, George O.
- Clark, George R.
- Clark, Gerald Wayne.
- Clark, Gowan C.
- Clark, Guy T.
- Clark, H L
- Clark, H. C. (Botanist)
- Clark, H. L.
- Clark, H. S.
- Clark, H. Walton (Howard Walton), 1870-1941
- Clark, Hamlet, 1823-1867
- Clark, Helen Goldthorp.
- Clark, Henry J.
- Clark, Henry James, 1826-1873
- Clark, Herbert A.
- Clark, Howard O. Jr.
- Clark, Hubert Lyman
- Clark, Hubert Lyman, 1870-1947
- Clark, Hugh E.
- Clark, Huon L.
- Clark, J Desmond
- Clark, J F Gates
- Clark, J. Allen (Jacob Allen), 1888-
- Clark, J. H.
- Clark, J. J.
- Clark, J. L.
- Clark, J. T.
- Clark, J., active 1789-1830
- Clark, James B.
- Clark, James L. (James Lippitt) 1883-1969
- Clark, James Matthew, 1956-
- Clark, James, 1862-
- Clark, James, (Farrier)
- Clark, Janet Howell, 1889-
- Clark, Janice, 1948-
- Clark, Jerome B.
- Clark, Jim
- Clark, Joe.
- Clark, John B.
- Clark, John H.
- Clark, John L. (John Littner)
- Clark, John R.
- Clark, John R. (John Robert)
- Clark, John R. (John Russel). 1927-2010
- Clark, John S., 1885-1956
- Clark, John S., active 1885-
- Clark, John T. C.
- Clark, John Willis, 1833-1910
- Clark, John, 1909-1967
- Clark, John, active 1678-
- Clark, Jonathan D.
- Clark, Joseph, 1782-1858
- Clark, Josephine A. (Josephine Adelaide), 1856-
- Clark, Josephine F
- Clark, Judson Freeman, 1870-
- Clark, Julia A.
- Clark, Julia E.
- Clark, Karen L
- Clark, Kathleen A.
- Clark, Kerry B.
- Clark, Kevin B
- Clark, Khrystin R.
- Clark, Kirstin.
- Clark, L. M.
- Clark, Larry
- Clark, Lee.
- Clark, Leila F
- Clark, Leonard B
- Clark, Linda S
- Clark, Lindie
- Clark, Lois
- Clark, Lynn G.
- Clark, M J
- Clark, M S
- Clark, Malcolm R. 1956-
- Clark, Margaret
- Clark, Margaret E
- Clark, Mark
- Clark, Marvin R., 1840-
- Clark, Mary A.
- Clark, Mary E
- Clark, Mary G
- Clark, Mary K.
- Clark, Mary, active 1677-1696
- Clark, Megan
- Clark, Michelle
- Clark, N. W.
- Clark, Neata
- Clark, Neil D L
- Clark, Nelson Of London
- Clark, Paul F
- Clark, Peter
- Clark, Peter W.
- Clark, Phil
- Clark, R. A.
- Clark, R. B.
- Clark, R. L.
- Clark, Ralph M
- Clark, Raymond S.
- Clark, Review By: Ernest D
- Clark, Richard J
- Clark, Robert
- Clark, Robert Brown, 1914-2005
- Clark, Robert G.
- Clark, Robert J
- Clark, Robert Louis.
- Clark, Robert Sterling.
- Clark, Roberta L.
- Clark, Roger N. (Biologist)
- Clark, Roger N. (Wildlife conservationist)
- Clark, Ross C
- Clark, Ruth
- Clark, Ruth P.
- Clark, S.
- Clark, S. A. (Stephanie Ann)
- Clark, S. B.
- Clark, S. H.
- Clark, Sandra
- Clark, Sarah
- Clark, Scott T.