(The Mishnah taught that) he shouldn't introduce there another seed, even inside a (hollowed out) gourd or in a pipe. This is when the pipe wrapped around the vine is made from earthenware (so it doesn't prevent the Kilayim mixing) but if it's made from metal, one does not need to have three Tefachim of soil above it.

(The Mishnah taught that) if he was Mavrich it into a rock (even if there are only three fingerbreadths on top of it, it is permitted to bring another seed). This is when the rock is hard (and doesn't allow roots to penetrate it), but if it's soft, it is penetrated by the roots.

(The Mishnah taught that a bent vine in a vineyard is measured from the second root.) This is only when the first root is not visible, but if it is, one must distance 6 Tefachim from each of them.

This is certainly true, as the next Mishnah teaches, "One who was Mavrich three vines and their original roots are (also) visible" (they are treated like a vineyard with two rows of vines); and a Baraisa teaches that this is for the law of vineyards (as each vine comes out in two places) but for work access, each (vine root is viewed as a single vine and) requires 6 Tefachim.

(Mishnah): One who was Mavrich three vines and their original roots are (also) visible - R. Elazar bei R. Tzadok says - if there are between 4 and 8 Amos between them, they combine (to be considered a vineyard and require a work access separation before planting); if not, they do not combine.

If a vine dried out, it is still prohibited (to plant nearby because of Maris HaAyin) but it doesn't prohibit (the product if a person transgressed).

(R. Meir): The same law applies to (planting near) a cotton plant (since its leaves look like vine leaves), that it is (Rabbinically) prohibited but it doesn't prohibit (if a person transgressed).

(R. Elazar bar R. Tzadok citing R. Meir): (In the case of the previous Mishnah in Menachos 77-1(a) of a person who was Mavrich a vine, that if there aren't three Tefachim of earth on top of it,) he also shouldn't plant above the vine, but it doesn't prohibit (if he transgressed).

In the following cases it is prohibited (to plant) but it doesn't prohibit (if he transgressed) - in the added distance required for a Karachas (patch) in order to be able to plant (although 4 Amos around it should have been enough, the Mishnah earlier (Menachos 55 (a)) cited a dispute as to whether it must be 16 or 24 Amos); (similarly) in the added distance of a Mechol HaKerem (the perimeter area between the vineyard and its fence - if there aren't 12 Amos there, one may not plant, even though there are 4 Amos); in the added distance of an Aris (in the Mishnah earlier Menachos 75 (a), that gaps in an Aris must be a little over eight Amos); in the added distance of an Apifiros (see Menachos 74 -1 (a) - a lattice work that supports a vine).

But if one plants under a vine that spreads over seeds, or within the 6 Tefach work access of a vine, or within 4 Amos of a vineyard, they prohibit and must be burned.

(Gemara): This Halacha (that if a vine dried out, it is still prohibited to plant nearby) follows R. Meir (whose opinion the Mishnah continues to bring).

Question: This is understandable in the winter (that there could be a problem of Maris HaAyin, as living vines appear lifeless), but in the summer (when it is clear that the vine is dead, what's the problem)?

Answer: There are some places where the leaves fall from the vines even in the summer (so a person might think that the dried out vine is still alive).