(Mishnah): One may not separate Terumah from one species for another species and if he did, it is not valid. All types of wheat are considered one species; all types of figs, dried figs and fig cakes are considered one species and one separates from one for another. Wherever there is a Kohen present, one separates from the superior type; whenever there is no Kohen present, one separates from the type that is longer lasting.

(R. Yehuda): He always separates from the superior type.

One separates a whole small onion rather than half a large onion.

(R. Yehuda): No, he separates half a large onion (even though the whole small onion is longer lasting).

(R. Yehuda): One may separate from the town-grown onions for the village-grown onions but not vice-versa, since the town-grown onions are eaten by important people (even though the village-grown ones are longer lasting).

(Gemara) (R. Yochanan citing R. Yannai): The following is one of three clear Derashos about Terumah...

The pasuk states (Bamidbar 18:12), "The choice of the oil and the choice of the wine and grain'' - what's the case? If it's to teach that one may separate Terumah from oil for grain and vice versa; it cannot be true, as if wine and oil, which are two species of tree, may not be separated for each other, then certainly wine and grain where one is from a tree and one from the ground, certainly one may not be separated for the other!

Rather, just as wine and oil, that are two species of tree, may not be separated for each other, so too two species of grain (e.g. wheat and barley) may not and two species of produce (e.g. beans and lentils) may not.

The Mishnah taught: All types of wheat are considered one species. This teaches that even white wheat for red wheat or vice versa is valid.

(Baraisa): One may separate figs for dried figs by number and dried figs for figs by measure; but not figs for dried figs by measure, nor dried figs for figs by number (as these ways will cause a loss to the Kohen).

(Rabban Shimon ben Gamliel): Baskets of figs and dried figs are one species. (The Gemara will explain the meaning of this.)

(R. Yishmael bei R. Yosi disagrees): (One may separate dried figs for figs by number.) My father would take out 10 dried figs from the area where they were dried as the Terumah of 90 figs in the basket (even though dried figs are smaller than fresh figs).

(What was the reasoning of R. Yishmael bei R. Yosi?) R. Yirmiyah thought that R. Yosi viewed the shrunken fig as if it is expanded to its regular size, so he would take baskets of regular figs viewing their volume as the same as the dried figs separated as Ma'asros.

(R. Yona and R. Yosi, disagreeing with R. Yirmiyah): It's the way of a fresh fig to shrink but not the way of a shrunken fig to expand. So R. Yosi would take large baskets of fresh figs in place of small baskets of dried figs that were separated as Ma'asros.

(R. Acha to R. Yona and R. Yosi): Your Rav, R. Ila, also questioned (R. Yirmiyah's teaching).

(Mishnah in Maseches Taharos 3:4): If Tamei food the size of an egg (which is therefore large enough to contract the Tumah of food) was left out in the sun and it shrank, and the same applies to an olive-sized piece of Neveilah, a lentil kernel-sized piece of a creeping thing, an olive-sized piece of Pigul meat or Nosar meat or of Chelev, they are all Tehorim (i.e. they cannot convey Tumah).

(Dromai - the Rabbis of the South): (Commenting on the end of that Mishnah that if rain fell on those items and they expanded, one would be liable for eating them if he ate the Pigul or Nosar) It's only when they were originally the required size (and they subsequently shrank in the sun and expanded in the rain).

(R. Yochanan and R. Shimon ben Lakish disagree): It applies even if they were not originally the required size.

(Mishnah in Menachos 5:1): (According to R. Meir, the loaves of the Todah offering and of the Shtei Halechem (the two breads offered on Shavuos) are leavened by removing a small amount of flour from the Mincha itself and then kneading it in dough. It is then used to leaven the Mincha. According to R. Yehuda, sour dough from elsewhere is put in the measuring cup and then flour is added until it is filled up.) They said to him (R. Yehuda), "A Mincha would also be lacking or in excess (since the sour dough disturbs the required volume of flour)''.

Question: Who is the opinion referred to as 'they said to him'? It's R. Meir. Sometimes the sour dough is good quality and expanded and had it been fine flour, it would have been more contracted. You must view the expanded sour dough as if it is contracted, so the Mincha is considered to be lacking. And sometimes the sour dough is poor quality and contracted, and had it been fine flour, it would have been more expanded. And you must view the contracted sour dough as if it is expanded, so the Mincha is considered to be in excess.

R. Yirmiyah, R. Yochanan and R. Shimon ben Lakish all said the same about it being in excess. (R. Yirmiyah said earlier (i) that we view the shrunken as if it is expanded. R. Yochanan and R. Shimon ben Lakish disagreed with the Dromai earlier (see (m)&(n))).

R. Yona, R. Yosi and the Dromai all have the same view about it being lacking. (They all reason that it's not the way of a shrunken fig to expand.)

The people of the house of Pati cooked rice and forgot to tithe it...

(Chevraya): He should separate an amount from the raw rice corresponding to the cooked rice (like the opinion of R. Yona and R. Yosi, that one does not view the shrunken produce as if it is expanded).

(R. Yosi to Chevraya): I also agree there that we view it as if it's expanded (without the need to separate from raw rice), since rice is usually eaten cooked (and expanded).