Marijuana (C. sativa, C. indica, and C. rubeydis) is native to Asia (and possibly Africa), not the new world.
Other new-world plants include peanuts, pineapples, sweetpotatoes, numerous legumes, cashews, papayas, squashes, and guavas. Cotton appears to have been domesticated both in the old world (short-staple cotton) and new world (long-staple cotton).
Good call, my mistake. Heyerdahl (and others before and since) claimed that American domesticated cotton is a hybrid between wild cotton and old-world cotton. Couldn't find anything when I looked just now.