One who makes a neder prohibiting greens is permitted gourds; R' Akiva, however, forbids [them]. They said to R' Akiva: Doesn't a person say to his agent: “Buy me greens,” and he says: “I found only gourds”? He said to them: Indeed, it is so; but does he say to him: “I found only legumes”? [It is] only [because] bitter gourds are included under the category of greens, but legumes are not included under the category of greens. He is forbidden fresh Egyptian beans, but permitted dry [ones].