paw paw, the Asimina triloba species.

Newly Discovered Herbs Revealed for Healing Cancer and Other Diseases
Monday, August 16, 2010 by: Paul Fassa, citizen journalist
http://www.naturalnews.com/029482_herbs_cancer.html

(NaturalNews) Two related herbs, pawpaw and graviola, have proven effective against cancer cells in vitro (lab tests not involving mammals) while not adversely affecting non-cancer cells. In other words, they are potential non-toxic cancer cures. Even Sloane-Ketterer established that graviola has cancer cell resisting properties and doesn't damage healthy cells. However, private research proves that pawpaw is even more potent than graviola for curing cancer.

There are even reports of success with Lyme Disease using standardized pawpaw.

Introduction to Pawpaw http://www.pawpawresearch.com/pawpaw-intro.htm
The pawpaw tree is indigenous to several areas of North America

There are about eight different species of pawpaw; however it is the species Asimina triloba that was used by Dr. Jerry McLaughlin in his research, and it is only this species that contains the special annonaceous acetogenins that have been shown to so powerful in fighting insects, cancer cells, parasites, lice, and other attackers. The pawpaw is a cousin to the fruit known as graviola, but research has proven that although graviola has some similar natural chemical compounds, it is not as desirable or as powerful as Asimina triloba for medical use.

Uses of Pawpaw
Of course, the main use of pawpaw historically has been one of food and nutrition.