Bikkurim, Chapter Three, Mishnah Nine
In mishnah three we learned that they would decorate the baskets with beautiful fruits. In our mishnah two sages debate how they would decorate the baskets.
1) Rabbi Shimon ben Nanas says: they would decorate the bikkurim [with produce] other than the seven species.
2) But Rabbi Akiva says: they may decorate only with produce of the seven kinds.
Section one: According to Rabbi Shimon ben Nanas, they were allowed to decorate the bikkurim baskets with any kind of produce, even produce that is not one of the seven species from which one brings bikkurim.
Section two: Rabbi Akiva says that just as the bikkurim themselves come only from the seven species, so too the fruits used as decoration may come only from the seven species. He seems to be concerned lest it seem that they are bringing bikkurim from other species, and therefore he rules that even decorative produce must also be of the seven species.