1897: with his brother-in-law Léon Le CLerc, Ferdinand became owner of Forgeot et Compagnie, renamed Cayeux-Le Clerc. (see: Richard Cayeux, Histoire de la Maison Cayeux, Hommes et Plantes n° 25, 1998 or Iris et Bulbeuses, n°134, 1999, pp. 10-14).
Other members of the Cayeux family: Henri (brother), René (son), Jean (grandson), Richard (great-grandson).
The 1939 checklist notes: "Ferdinand Cayeaux 124 rue Camille-Groult, Vitry-sur-Seine, France, the most famous French Iris breeder, President, Chambre Syndicale des Marchands Grainiers Francais, Vice-President Société Nationale d'Horticulture Française. Awarded the Foster Memorial Plaque in 1935. For list of his Dykes Medal winners see under Cayeux. In 1938 Cayeux and his partner Mons. Le Clerc retired but Mons. Cayeux continues his work in hybridizing Irises and it is hoped, will do so for many years."
See a view of Petit Vitry's Nurseries (May 28th, 1925) on Cayeux et Le Clerc catalog 1930, p. 14.