Mayapple (Left: Podophyllum peltatum (L.)) (Berberidaceae) Edible ripe fruit, but the rest of plant toxic.  Root contains Anti-mitotic agent modeled from lignan chemistry of plant to treat small cell lung cancer and testicular cancer. (More)

Fruit when ripe may be made into jam or jelly. Native Americans smashed and dried fruit for later use.  Fruit cakes as they were called were reconstituted in water and used as a sauce.

Left: flower. 
Below left: unfurling leaf.  
Below:
unfurled leaf.  (Also)

Below see Native American Uses.

Native American Uses:  Root (toxic) used to kill worm infestations; emetic and purgative root; powerful laxative; root powder used externally on difficult to heal sores; juice of fresh root (one drop) put in the ear to improve hearing.

 

Note:  Corn seeds were soaked in root juices to discourage pests.