Mishnah 6 in chapter 6 also deals with fenugreek. Let us recall the principle that was explained: in fenugreek the seeds are fit for eating while the stalks are not fit for eating, yet the taste of the stalks is like the taste of the seeds - the taste of fenugreek.
Bundles of fenugreek that are kilei hakerem:
"Mi shehayu lo chavilei tiltan shel kilei hakerem - yidaleku" - someone who had in his possession bundles of fenugreek stalks with fenugreek seeds on them, and they grew in a vineyard and became kilei hakerem (forbidden mixed growths of the vineyard), their law is that they must be burned. Both the seeds, which are fit for eating, and the stalks, which are not fit for eating - all of them require burning, because all of them are kilei hakerem.
Bundles of fenugreek that are tevel:
"Hayu chavilei tiltan shel tevel" - he had in his possession bundles of fenugreek from which Terumah and tithes had not been separated, and the bundles include the stalks and the seeds together. He must tithe them and give the kohen the proper measure from the seeds, one fiftieth.
"Kotesh umechashev kamah zera yesh bahem umafrish es hazera" - this does not mean pounding in a mortar with a pestle, but rather beating the bundles in order to detach the seeds from them. He beats out some of the seeds, estimates on their basis how much seed there is in all the bundles, and separates the required measure.
For example: if he estimated that the total seeds in all the bundles amount to fifty cups, it is enough for him to beat out one cup of seeds and give it to the kohen as Terumah, and leave the rest attached to the stalks. It is a general rule regarding Terumah that it is given by estimate and there is no obligation to measure it precisely, and therefore this is proper even at the outset.
"Ve'eino tzarich lehafrish es ha'etz" - there is no need to give the kohen the stalks together with the seeds, since they are not fit for eating.
He separated the stalks together with the seeds:
Even though the stalks are not fit for eating, their taste is like the taste of the seeds. Therefore, although they cannot be Terumah by Torah law, they can be Terumah by rabbinic law when he designated them as Terumah.
Therefore, a person who had before him fifty stalks laden with seeds and said: one stalk with its seeds shall be Terumah - "im hifrish, lo yomar: echtosh ve'etol es ha'etz ve'eten es hazera, ela nosen es ha'etz im hazera". He may not first beat out the seeds, give them to the kohen, and keep the stalks for himself as animal fodder. Since he designated the stalk along with the seeds as Terumah, and since a special rule applies to fenugreek - that the taste of the stalk is like the taste of the seed, so that it is usable as far as taste is concerned - he must give the kohen the stalk and the seed together.
In summary: this mishnah explained two laws regarding bundles of fenugreek. With kilei hakerem - the seeds and the stalks alike require burning. With tevel - he beats out some of the seeds, estimates their total quantity and separates Terumah from them, and he need not separate the stalks along with them; but if he separated a stalk with its seeds and designated it as Terumah, then because the taste of the stalk is like the taste of the seed, he gives the wood together with the seed to the kohen and does not keep it for himself.