Reference for Bava Kamma 191:6
בעי רבא השביח עובד כוכבים מהו א"ל רב אחא מדפתי לרבינא תקנתא לעובד כוכבים ניקו ונעבוד אמר ליה לא צריכא כגון דזבניה לישראל סוף סוף הבא מחמת עובד כוכבים הרי הוא כעובד כוכבים
for [the benefit of] a heathen? — He said to him: No; the query might refer to the case where. e.g., he sold it to an Israelite. [But he retorted:] Be that as it may, he who comes to claim through a heathen [predecessor], could surely not expect better treatment than the heathen himself. — No: the query could still refer to the case where, e.g., an Israelite had misappropriated an article and sold it to a heathen who improved it and who subsequently sold it to another Israelite. What then should be the law? Shall we say that since an Israelite was in possession at the beginning and an Israelite was in possession at the end, our Rabbis would also here make [use of] the enactment, or perhaps since a heathen intervened our Rabbis would not make [use of] the enactment? — Let it remain undecided. R. papa stated: If one misappropriated a palm tree from his fellow and cut it down, he would not acquire title to it even though he threw it from [the other's] field into his own land, the reason being that it was previously called palm tree and is now also called palm tree.<span class="x" onmousemove="('comment',' [The change involved does not confer ownership enabling him to make restitution by payment in money.] ');"><sup>10</sup></span>