(a) In a case where the owner re-sowed one of the boxes, Rebbi Meir rules - that the second box is subject to Terumah and Chalah, whereas Rebbi Yossi holds that it is not (see Tiferes Yisrael).
(b) If somebody else sowed the second box - it is Patur (as we explained in the previous Mishnah).
(a) In a regular case, where someone sows Terumah seeds be'Shogeg - unless he digs up the ground where they are growing, whatever grows becomes forbidden.
(b) The seeds will be Asur (like the boxes were in the previous cases) should the owner re-sow both boxes - if it is a species of plant whose seed does not rot completely in the ground ('Davar she'Ein Zar'o Kalah').
(c) An example of 'Davar she'Ein Zar'o Kalah' is - garlic and onion seeds.