The Mishnah taught - When must a quarter Kav be reduced? (When grain is mixed with grain (e.g. wheat with barley); beans with beans (e.g. beans and lentils) and beans with grain.) The Baraisa teaches - For example, 3 or 4 Kav, but if there are only 2 Kav, it is 1/24th.

The Mishnah taught, "In truth they said that garden seeds that are not eaten combine to be 1/24th in a Beis Seah." R. Elazar said that whenever they used the phrase 'in truth they said', it signifies a Halacha L'Moshe MiSinai (an oral tradition originating at Har Sinai). And a Baraisa taught about this (see earlier Menachos 31-(g)1.) - (When does this apply?) For example, only a Kav or half a Kav of garden seeds is needed per Beis Seah - so if a certain species of garden seed needs two Kav per Beis Seah, it's viewed like grain and it prohibits a Se'ah of seed only if it was a Rova.

In the second Baraisa you say that if two Kavs suffice for a Beis Seah, a Rova prohibits and in the first Baraisa you say that if two Kav suffice for a Beis Seah, 1/24th prohibits.

(R. Zeira/ R. Avuna disagreed in citing Rav Huna): One said that any species that is sown up until 9 Kav per Beis Seah (is the upper limit to be included in the category of grain and legumes for the rule of one Rova per Seah) and one said until 8 Kav.

Question: If one type of seed is sown at 9 Kav per Beis Seah and another is sown at 10 Kav, do they combine (to prohibit)?

Answer (Baraisa): Two seeds, one sown at 9 Kav and one type at 3 Kav, combine.' If 9 and 3 combine, certainly 9 and 10 combine!

Rebuttal (R. Avin and R. Chanina): A 9 Kav seed and a 3 Kav seed do not combine (as their required quantities are so different). Any seed that is sown between 3 Kav and a Seah per Beis Seah combine. Any seed that is sown between a Seah and 9 Kav per Beis Seah do not combine.

Therefore, a Rova of a seed of which a Seah is sown combines and prohibits a seed of which 3 Kav is sown. Similarly, a Rova of a 3 Kav seed combines and prohibits a Seah seed. Also, a Rova of a Seah seed combines and prohibits a 9 Kav seed and a Rova of a 9 Kav seed combines and prohibits a Seah seed.

The Mishnah taught - '(Therefore) flax (that needs 3 Seah to seed an area of a Beis seah) that was mixed with grain, would also follow the rule of 1/24th.' This means that three Rova of flax prohibit a Seah of regular seed.

How is this so? In an area in which a Rova of wheat is sown, three Rova of flax is sown.