Of the two genera of Piperaceae (Piper and Peperomia), the former may be more primitive (Bentham and Hooker 1880, De Dalla Torre and Harms 1900-1907, Hutchinson 1969). According to Rousseau (1927), Piper is the basic group from which Chloranthus and Saururus (commonly placed in distinct families) are derived by minor modification, while Peperomia has evolved by major changes. Anatomical study (Metcalfe and Chalk 1950) suggest Piper to be most specialized. Study of karyotype is an important field of research for understanding interrelations and evolutionary trends (Darlington 1937, White 1945, Babcock, Stebbins and Jenkins 1937, Love 1946, Kapoor and Love 1970, Asana and Adatia 1945, Bowden 1945, Tobgy 1943, Stebbins 1964, 1966, Sharma 1960). A few authors (Smith 1966, Mathew 1958, Sharma and Bhattacharyya 1959, Blot 1960) have studied the karyology of the family with special attention to phylogeny. Solution of phylogenetic problems requires further comparative study of chromosome morphology. © 1976, Japan Mendel Society, International Society of Cytology. All rights reserved.