Mishnah 3 deals with property that came to a woman through inheritance after she was married, and with the husband's right to consume its produce. The basic question is how to handle each type of asset, so that the principal remains the wife's while the produce goes to the husband.
Money came to her:
The Mishnah rules: "Naflu lah kesafim - yilakach bahen karka vehu ochel peiros" - if money came to her, land is purchased with it and he consumes the produce. Cash that simply sits there produces nothing, while the husband's right is only to consume produce. Therefore land must be bought with the inherited money, so that the principal remains the wife's while the husband enjoys the produce that the land yields.
Detached produce came to her:
Produce that has already been detached from the ground is no longer part of it, and its status is exactly that of cash. For this reason the law regarding it is identical: "Yilakach bahen karka vehu ochel peiros" - land is purchased with it and he consumes the produce.
Produce attached to the ground came to her:
Here the main question arises. A woman inherited land with produce attached to it at the moment the inheritance came to her - what is the status of that produce? Must the produce grow only after the land was already hers and the husband already had rights in it, or is it enough that the produce is attached to the land for it to be considered produce to which the husband is entitled?
The Tannaim disagree on this question:
Rabbi Meir: "Shamin osan kamah hen yafin b'feiros v'chamah hen yafin b'lo feiros" - we assess how much the land is worth with the produce and how much it is worth without the produce. That is, we evaluate the value of the land with the produce attached to it and its value without the produce, and the difference between the two is considered principal. In his view this produce does not have the status of produce that the husband consumes, and therefore land must be purchased with the amount of the difference, and the husband consumes its produce.
The Sages: "Hamechubar lakarka - shelo" - whatever is attached to the ground is his. Anything that was attached to the ground at the moment the inheritance came to her belongs to the husband, since its status is that of produce which the land yielded and not that of principal.
In contrast, "V'hatalush min hakarka - shelah" - and whatever is detached from the ground is hers: produce that had already been detached at the moment the inheritance came to her belongs to the wife, since its status is that of cash, and as explained above, land is purchased with it and the husband consumes its produce.
In summary: in this Mishnah we learned three cases of property that came to a woman after her marriage: money and detached produce, with which land is purchased and the husband consumes its produce; and produce attached to the ground, regarding which Rabbi Meir holds that it is principal and assesses the difference between the value of the land with the produce and its value without it, while the Sages hold that whatever is attached to the ground at the time of the inheritance is his, and whatever is detached is hers.