Chromosomal Conspectus of the Euphorbiaceae

Summary Generic interrelationships, evolution and ancestry of the family Euphorbiaceae is reviewed from a chromosomal point of view with the world wide data including the author's record of 43 species from the eastern Himalayas. The arrangement of genera is according to Bentham and Hooker's system of classification and repeated references are made to Hutchinson's recent view of tribalism in the family. The family is believed to be polyphyletic having at least two base numbers x = 7 and 13. The other base numbers encountered in the family are x = 6, 8, 9, 10, 11, 12, 15, 16, 17 and 18 coupling with the well known morphological and taxonomical complexity of the family. The Euphorbiaceae seem to be of Asiatic origin and primitive ***Phyllantheae may have evolved in the New World. Both polyploidy and aneuploidy are effective in speciation and as much as 48 per cent of the known taxa exhibit polyploidy.