פירוש על קידושין 77:1

But, Ulla continues, according to Shmuel’s view, there should be no difference in the rules governing buying orlah and kilayim from a Gentile outside the Land. Both have the same status—prohibited by the rabbis.

Shmuel did indeed emend one of the mishnayot such that both read the same. Thus he accepted Ulla’s criticism.

Mar son of Rabbana, a late amora, was lenient in both cases—as long as the Jew does not gather the orlah or kilayim, the produce is not prohibited.