1. Roy. Hort. Soc. Dictionary of gardening. (4 v.,1951; lists 3,216 species) the best place to start; 2. A.D.Hawkes' Encyclopaedia of cultivated orchids . (1965; has only 2,192 species, plus a lot that have never been cultivated); 3. Bechtel, Cribb and Launert's The manual of cultivated orchid species; (1981; lists only 967 species but provides a colored illus. of each flower). OR85-16; RMH