Two types of wild bean grow along the D&R Canal in Princeton. Groundnut (Apios americana) has reddish flowers in August followed by beans in September that look much like green beans you'd grow in your garden, but it gets its name from the edible tubers that grow along its roots. For details, see http://www.pfaf.org/database/plants.php?Apios+americana. Note that each leaf has five leaflets. Hog peanut--another leguminous vine growing along the canal--has three leaflets. Asian wistera, fortunately not common in this area, has many more leaflets than either of these two natives.