Nedarim 84: The Pool of Poor People

A woman who has sworn off benefit from people, and can still eat from the agricultural mitzvot of charity, but it doesn't mention ma'aser ani. But is that lack of mention because she can't eat from ma'aser ani? What are the implications of demai (uncertainty with regard to whether tithes have been taken). Note that ma'aser ani doesn't have kedushah, as some other such mitzvot do. Also, the question of when one can designate the recipient of such gifts to the poor may carry monetary value (or not).