charles darwin concluded that carnivory in plants was convergent, writing in 1875 that carnivorous genera "utricularia" and "nepenthes" were not “at all related to the [carnivorous family] droseraceae.”  this remained a subject of debate for over a century. in 1960, leon croizat concluded that carnivory was monophyletic, and placed all the carnivorous plants together at the base of the angiosperms.  molecular studies over the past 30 years have led to a wide consensus that darwin was correct, with studies showing that carnivory evolved at least six times in the angiosperms, and that trap designs such as pitcher traps and flypaper traps are analogous rather than homologous.