Gemara

59b (Mishnah - R. Shimon): If it ate finished fruits (it pays the full value).

Question: "It will consume in a different field" teaches that we evaluate like part of a field!

Answer: That is only when it eats something that needs (to grow more in) a field.

(Rav Huna bar Chiya): Rav taught that the Halachah follows R. Shimon.

76b: R. Shimon holds that whenever the blood is destined to be thrown (i.e. after slaughter), it is as if it was thrown (and the animal was permitted immediately). He holds similarly about anything ready to be redeemed.

(Beraisa - R. Shimon): A red heifer receives Tum'ah like a food because there was a time when it was ready to be eaten.

(Reish Lakish): He permits redemption even (after slaughter) near the wood (prepared for burning it). It is as if it was redeemed, and it receives Tum'ah.

Kesuvos 50b: Rav Yosef ruled that daughters be fed from dates on mats, i.e. ready to be (detached and) put on mats.

Question: What is ready to be detached is considered to be detached!

Answer (Rav Yosef): I discuss dates that must remain on the tree a little longer.

Gitin 39a (Beraisa): If one was Makdish his slave, Me'ilah does not apply;

R. Shimon ben Gamliel says, Me'ilah applies to his hair.

They argue about hair ready to be cut (whether it is as if it was already cut).

Suggestion: They argue as the following Tana'im argue.

(Mishnah - R. Meir): If Reuven claimed 'I entrusted you with 10 laden vines, and Shimon said 'you entrusted me with only five', he must swear.

Chachamim say, anything attached is like land; he need not swear.

(R. Yosi b'Rebbi Chanina): They argue about grapes ready to be detached. Meir considers them as if they were already detached; Chachamim disagree.

Rejection: Chachamim of the Beraisa can hold like R. Meir. He considers grapes as if they were detached, because they get worse if left attached too long (surely, they will be detached soon). Hair increases in value the longer it is attached!

Rishonim

Rif and Rosh (Shevu'os 24a and 6:24): We established that R. Meir and Chachamim argue about grapes ready to be detached.

Ran (DH Masnisin Yesh): We say in Kesuvos that anything ready to be detached is as if it were already detached, this is when it does not need the land at all. When it needs the land a little, but if it stays attached too long it will be ruined, Chachamim and R. Meir argue.

Rif (Kesuvos 18b): What is ready to be detached is considered to be detached.

Rambam (Hilchos Sechirus 2:4): If one entrusted attached Peros to be guarded, even grapes ready to be detached, they are like land regarding laws of Shomrim.

Rambam (Hilchos To'en 5:4) If one claimed grapes ready to be detached, and Shimon admitted partially, he swears about it like other Metaltelim. This is if they do not need the land anymore. Anything ready to be detached is considered detached for denial and admission. If they still need the land, they are like

Magid Mishneh: The Rambam holds that all agree that anything ready to be detached is considered detached. The Tana'im argue about Peros that do not need the land; he rules like R. Meir. Alternatively, all agree that Peros that do not need the land at all are like Metaltelim. Kesuvos 51a is like Chachamim, and the Rambam rules like them. The Rambam ruled similarly in Hilchos Mechirah (1:17). However, in Hilchos Sechirus (2:4) the Rambam says that even if they do not need the land, they are like land regarding Shomrim. Why should we distinguish Shomrim from other matters?

Hagahos Maimoniyos (4): The Halachah follows R. Shimon, that if it ate finished fruits it pays the full value, for it is as if they were detached.

Beis Yosef (CM 95 DH v'Chosav ha'Rambam): The Rambam holds like his Rebbi, Ri ha'Levi, that R. Meir and Chachamim argue only about Shomrim, but for everything else Chachamim agree that anything ready to be detached is considered to be detached. The Gemara in Kesuvos is like everyone. A proof of this is that the Rambam rules that for Kinyan it is like Metaltelim, and regarding Shomrim it is like land.

Drishah (95:5): In Hilchos To'en (5:4) the Rambam said 'grapes ready to be detached...', and added 'this is if they do not need the land any more.' He explains that the Tana'im argue about grapes ready to be detached, but they still need the land a little. (The Gemara said 'all agree about grapes that need the land', i.e. they are not ready to be detached at all.) He distinguished like this so that the Gemara in Kesuvos is like Chachamim, and rules like them.

Poskim

Shulchan Aruch (CM 95:2): If Reuven claimed grapes ready to be detached, and Shimon partially admitted, he swears about it like about other Metaltelim.

Tur: Ri ha'Levi says that if one sold grapes ready to be detached, since he intends to detach them, they are like Metaltelim in every way, e.g. Ona'ah and Shevu'ah. Regarding a Shomer they are considered attached, for he intended that they stay attached. The Ramah says that they are excluded from everything from which land is excluded: Shevu'os, theft, and Ona'ah.

Shach (9): In Gitin (39a) we say that R. Meir discussed only grapes, which get worse if left in the ground. The Ran says that they need the land a little, but afterwards they would get ruined. Ri ha'Levi and the Rambam distinguish between Shomrim and other matters; I disagree. There is no reason to distinguish. Tosfos Yom Tov (Shevu'os 6:6) asked that if they are like Metaltelim only for Shomrim, why does the Mishnah discuss partial admission? In any case he must swear, for he is a Shomer! The Rif, Rosh and other Poskim hold that Chachamim consider it like land in every respect. Why did the Gemara suggest that the argument about Hekdesh of a slave is like the argument of R. Meir and Chachamim? It does not discuss a Shomer! A widow does not rely on collecting attached Peros, for the orphans can harvest them if they want. For everything else, attached Peros are like land. The Ra'avad said that we do not learn from Shevu'ah to other matters. Perhaps he means that we do not learn from Shevu'ah or other mid'Oraisa matters to collection of debts, which is mid'Rabanan.

Gra (12): The Rambam (Hilchos Me'ilah 5:10) holds that something attached is like Metaltelim if it will deteriorate if left attached, like R. Meir. This is like Ri ha'Levi, who says that they are like land only regarding Shomrim. For damages, if an animal ate attached produce, Rav rules like R. Shimon.

Shulchan Aruch (CM 193:1): If something attached does not need the land, e.g. grapes ready to be detached, they are Metaltelim for Kinyan and Ona'ah.

Shach (1): The primary opinion is the Rema, who is like the Tur. He did not bother to comment in Siman 95, for in any case mid'Rabanan one must swear. Here he commented, for land is not acquired like Metaltelim at all.

Note: How does he explain why the Rema did not comment above? There are differences between mid'Oraisa and mid'Rabanan oaths!

Gra (3): We hold like Chachamim only regarding Shomrim.

Rema: Some say that even if they do not need the land, they are like land.

Gra (4): This opinion rules like Chachamim regarding everything except for one who ate finished Peros, or what a creditor can collect.

Shulchan Aruch (CM 301:5): If one entrusted his friend to guard something attached to the ground, even if it was grapes ready to be detached, it is like land.