Related על מעשר שני 5:11

One may not take terumah from one type on behalf of a different type, but they said (Ter. 2:4), all types of wheat are one, [and] all types of beans, and nuts, and almonds, and pomegranates are one, [and] we [may] take terumah and tithes from one on behalf of the other. [If] someone had black figs and white [figs] inside his house, and similarly, two types of wheat, we [may] take terumah and tithes from one on behalf of the other. Rabbi Yitzchak says in the name of Rabbi Eliezer, Beit Shammai say, we do not take terumah [in such cases], and Beit Hillel say, we [are permitted to] take terumah.