ABSTRACT
The genera of the Cypenceae Juss. are largely distributed all over the world, and a few of them are endemics. Some times, they are of economic interest since some occur as weed in agricultural areas. The botanical identification is difficulted when only the frutiferous materials axe pieseoL So this work deals with external morphology of the fruits of the Cypenceae Juss. - the acnene looking for a generic identification of those occuring in Brazil, by using herbarium material. For such characteristics the achenes were grouped in five tyes: A - Naked Achenes; B - Perigynious Achenes; C - Styled Achenes; D - Mixed Achenes and E - Utriculed Achenes. A key for the identification of the 31 genera studied was made and also tried to follow the evolutionary pathway of the family, based on the morphological structures of the fruits.