- A & S Dahlia Gardens (Firm),
- A Village Garden (Firm)
- A. & A.D. Vanderkraats.
- A. & E. Waterhouse.
- A. & R. Spottiswoode.
- A. & S. Garden Shop (New York, N.Y.)
- A. A. Samuelson (Firm),
- A. and S. Matthews (Firm)
- A. B. Dodge (Firm),
- A. Barnes & Co.
- A. Bettesworth and J. Batley (Firm)
- A. Blanc & Co.
- A. Brackett & Son.
- A. Branson (Firm)
- A. Bresler, Son & Co.
- A. Burntrager (Firm)
- A. Clark Tuttle (Firm)
- A. Currie & Company.
- A. Daigger & Company.
- A. De Groot (Firm)
- A. Dietsch Company.
- A. Donaghue (Firm)
- A. Dulau & Co.,
- A. E. Curtis (Firm)
- A. Esteves, Flavia
- A. F. Wotipka (Firm)
- A. Fomichev, Alexander
- A. Ford & Co. (Johannesburg)
- A. G. Ammon,
- A. Gofferje (Firm)
- A. Griesinger Co., Inc.
- A. Gude Sons Co.
- A. Hamilton & Sons.
- A. Hance & Son.
- A. Ibrahim, Adel
- A. Jerome Pratt (Firm)
- A. Ladygo Nursery,
- A. Matoso, Daniele
- A. McGill & Son.
- A. Miller & Co.
- A. Miller & Sons, Inc.
- A. Mitting (Firm)
- A. Mueller Dahlia Gardens.
- A. N. Kanouse (Firm)
- A. Nadruz Coelho, Marcus
- A. Pastor Nursery.
- A. Pullen (Firm)
- A. Saul & Co.
- A. Summerville (Nursery),
- A. T. Glover (Firm)
- A. Tilton & Son.
- A. Tilton (Firm)
- A. Vanderkraats & Son.
- A. Washburn & Sons.
- A. Watson Armour III Spring Symposium Chicago, Ill.). 1999-
- A. Willis & Company.
- A. Willis (Firm)
- A. Wittemann (Firm)
- A., B. & A. Ry Co.
- A., Knight T
- A., Romanow K
- A.A. Ames (Firm)
- A.A. Berry Seed Company.
- A.A. Eastman (Firm)
- A.A. Grant
- A.A. Hart (Firm)
- A.A. McGinnis & Son.
- A.A. Richardson (Firm)
- A.B. Allen & Co.
- A.B. Austin (Firm)
- A.B. Austin Nursery Co.
- A.B. Cleveland Co.
- A.B. Davis & Son.
- A.B. de Groat (Firm)
- A.B. Farquhar Co.
- A.B. Flagg Co.,
- A.B. Hood & Co.
- A.B. Katkamier (Firm)
- A.B. Lyman (Firm)
- A.B. Lyman, Inc.
- A.B. Morse Company,
- A.B. Scott (Firm)
- A.B. Vanderbeek Bulbs.
- A.C. and A.T. Scott (Firm)
- A.C. Anderson (Firm)
- A.C. Arny-M.K. Arny (Firm)
- A.C. Benge (Firm)
- A.C. Doty (Firm)
- A.C. Heckman (Firm)
- A.C. Hoyt & Co.
- A.C. Keene & Son.
- A.C. Keene (Firm)
- A.C. Kendel (Firm)
- A.C. Kendel's Seed Store.
- A.C. Kinsey (Firm)
- A.C. Nellis & Company (Canajoharie, N.Y.)
- A.C. Nellis (Firm)
- A.C. Nellis Co.
- A.C. van Eeden & Co.
- A.D. Birdsall (Firm)
- A.D. Cribbs (Firm)
- A.D. Field (Firm)
- A.D. Field Bulb Gardens.
- A.D. Hudson (Firm)
- A.D. Mebane Cotton Seed Company.
- A.D. Perry & Co.
- A.D. Pratt (Firm)
- A.E. Bents & Son.
- A.E. Boothe & Son,
- A.E. Kunderd (Firm)
- A.E. Kunderd, Inc.
- A.E. Luedy Co.,
- A.E. McKenzie & Co.
- A.E. Spalding (Firm)
- A.E. Wohlert (Firm)
- A.E. Wohlert's Nurseries.
- A.F. Bloese & Son.
- A.F. Bloese (Firm)
- A.F. Boardman & Co.
- A.F. Mosby (Firm)
- A.F. Rice (Firm)
- A.G. Aldridge (Firm)
- A.G. Aldridge Estate.
- A.G. Aldridge Sons.
- A.G. Aldrige Sons.
- A.G. Blount & Sons.
- A.G. Blount (Firm)
- A.G. Blount Nurseries.
- A.G. Gelletly & Co.
- A.G. Goodacre (Firm)
- A.G. Griesa & Bros.
- A.G. Samuel (Firm)
- A.H. Austin Co.
- A.H. Chadbourne & Co.
- A.H. Griesa (Firm)
- A.H. Griesa Experimental Grounds.
- A.H. Heberle Nurseries.
- A.H. Hoffman (Firm)
- A.H. Hoffman Seeds, Inc.
- A.H. Hoffman, Inc.
- A.H. Hummert Seed Co.
- A.H. Nichols (Firm)
- A.I. Root Company.
- A.J. Anderson (Firm)
- A.J. Bernhardt (Firm)
- A.J. Dawson & Bro.
- A.J. Downing & Co.
- A.J. Greene (Firm)
- A.J. McGraw (Firm)
- A.J. McMath (Firm)
- A.J. van der Vies & Co.
- A.J. van Engelen Inc.
- A.J. Verhelle (Firm)
- A.J. Wilkus & Sons.
- A.J.A. Spafford (Firm)
- A.K. Clingman (Firm)
- A.L. & H.J. Bradley.
- A.L. Bancroft & Company.
- A.L. Bruce & Sons.
- A.L. Don & Co.
- A.L. Florin and Ben R. Bones (Firm)
- A.L. Florin and Ben R. Bones (Firm), Grants Pass, Oregon
- A.L. Gilbert (Firm)
- A.L. Hatch (Firm)
- A.L. Luke (Firm)
- A.L. Utz Bulb Gardens.
- A.L. Wood (Firm)
- A.L. Zimmerman (Firm)
- A.M. Davenport (Firm)
- A.M. Ferguson & Co.
- A.M. Grootendorst, Inc.
- A.M. Kittoe (Firm)
- A.M. Leonard & Son.
- A.M. Purdy & Son.
- A.M. Purdy (Firm)
- A.M. Ramsey & Son.
- A.N. Brown (Firm)
- A.N. Jones (Firm)
- A.N. Kinsman & Co.
- A.N. Pierson, Inc.
- A.O. Gilbertson (Firm)
- A.O. Gilbertson (Firm)
- A.O. Gilbertson Company.
- A.O. Gilbertson Company.
- A.O. Popp Seed Co.
- A.P. Bonvallet & Co.
- A.P. Saunders (Firm)
- A.P. Wright (Firm)
- A.R. Aldrich (Firm)
- A.R. Baker Dahlia Gardens.
- A.R. Davis (Firm)
- A.R. Pontius (Firm)
- A.R. Rideout Nursery.
- A.R. Weston & Co.
- A.R. Weston & Company.
- A.R. Zwaan & Son,
- A.S. Albert (Firm)
- A.T. Cook (Firm)
- A.T. Edison (Firm)
- A.T. Garey (Firm)
- A.T. Goldsborough (Firm)
- A.T. Hudelson (Firm)
- A.T. Lane (Firm)
- A.T. Remer (Firm)
- A.V. Keller Nursery Company,
- A.W. Alstott (Firm)
- A.W. Beebe (Firm)
- A.W. Brøggers Boktrykkeri A/s
- A.W. Burroughs (Firm)
- A.W. Dows & Co.
- A.W. Dows and Co.
- A.W. Eames (Firm)
- A.W. Hahn's Erben (Firm),
- A.W. Masser Seed House.
- A.W. Masser's Seed House.
- A.W. Schisler Seed Co.
- A.W. Smith (Firm)
- A.W. Smith Company.
- A.W. Steinbring (Firm)
- A.W. Warren & Son.
- A0, Meren
- Aa, Boudewijn Janssoon van der (II, Leiden)
- Aa, Pieter van der, 1659-1733
- Aaberg, Stephen A.
- Aabling Boyce Seed Company.
- Aabling Seed Farms, Inc.
- Aabling-Ebright Seed Co.
- Aabling's Seed Farms, Inc.
- Aaboe, Kim
- Aadland, C R
- Aagesen, Lone
- Aakjar, Ronald A.
- Aalbers, J
- Aalbers, Scott A
- Aalbu, Rolf
- Aalbu, Rolf L
- Aalbu, Rolf Lionel.
- Aalders, Lee
- Aalders, Lewis E.
- Aalto, Kenneth R
- Aangelo, Paula Cristina da Silva
- Aaraújo, Cláudio Vieira de
- Aaraujo, R J
- Aardema, Matthew L
- Aaroe, Georgene A.
- Aaron Low (Firm)
- Aaron, S F
- Aaronsohn, Aaron, 1876-1919
- Aaronsohn, M A
- Aaronson, Andrew C.