Berachos, Chapter 6, Mishnah 4. This mishnah addresses the following question: when a person has before him several different kinds of food that share the same berachah, which one does he recite the berachah on first?
The mishnah presents a case in which a person has many kinds of food before him and wishes to eat all of them. According to Rabbi Yehudah, if one of them is a species "mishivas haminim she'Eretz Yisrael nishtabchah bahem" - one of the seven species with which the Land of Israel is praised - that one takes precedence, and the berachah is recited on it first.
The order of precedence among the seven species:
The verse in Parashas Eikev states: "eretz chittah use'orah vegefen use'einah verimon, eretz zeis shemen udevash" - "a land of wheat and barley, vine and fig and pomegranate, a land of olive oil and honey" - and the "honey" mentioned here refers to date honey. The rule of precedence is determined by proximity to the word "eretz" (land): whichever species is closer to that word takes precedence.
However, the word "eretz" appears twice in the verse. The species adjacent to the first mention (wheat and barley) take precedence over the rest, but two species are also adjacent to the second mention (olive and honey), and they too take precedence over the remaining species. The result is an interwoven order among all the species: first the one adjacent to the first "eretz," then the one adjacent to the second "eretz," then the second one listed after each of them.
There is, however, an opinion that since the first species takes precedence in any case, the barley adjacent to it also takes precedence. According to that opinion, this is the order:
Wheat - the first of the species.
Barley - adjacent to it in the first mention of "eretz."
Olive - adjacent to the second mention of "eretz."
Dates - listed second after the second mention.
Grapes - and this applies when he is eating the grapes themselves; but wine made from grapes, since it has a berachah of its own, takes precedence even over them.
Figs.
Pomegranates - the last of the species.
All of this is according to Rabbi Yehudah. According to the opposing opinion, however, a person may choose which species to recite the berachah on: whichever is more significant in his eyes, the one he enjoys and desires more, is the one he recites the berachah on first.