Beis Shammai say: [Produce declared] owner-less for the poor [becomes] ownerless. But Beis Hillel say: It is not ownerless un-less it is declared ownerless with respect to the rich as well, as [is the case with] Shemittah. [If] all the sheaves of the field are each [the size] of one kav, and one is [the size] of four kavs, and he forgot that large [sheaf], Beis Shammai say that it is not [treated as] shich'chah, but Beis Hillel say that it is shich'chah.