daf bit: Nedarim 55

The mishna reports a dispute: if a man vows to abstain from grain Rabbi Meir says he is also forbidden dry Egyptian beans, but the sages say he is forbidden only the five grains. It was taught in a baraita [1] that he is also permitted rice, grist, groats, pearl-barley, and moist Egyptian beans. (My edition does not clarify what Egyptian beans are.) The gemara adds that if he vows to abstain from "the fruit of that year" he is forbidden all produce but is permitted lambs, milk, eggs, and fledglings; if, however, he vows to abstain from "the fruits of the earth", all this is forbidden to him too. (55a-b)

[1] A baraita is a teaching contemporary with the mishna that was not recorded therein. (The baraita is quoted in the gemara.)

(I had initially thought that the mishna about beans and the five grains might be a basis for the later Ashkenazi prohibition of kitniyot during Pesach, but not if rice etc is permitted in this case.)