Uktzin, Chapter 1, Mishnah 4. This mishnah continues the subject that opened the maseches: those parts of a fruit or a vegetable which are not eaten themselves, yet are attached to the food and serve it in one way or another. Some of them function as a shomer, a covering that guards the food and keeps it from spoiling. Others function only as a yad, a handle. Our mishnah presents a list of items that belong to the second group: they are used for holding the produce, but they do nothing to preserve it.
The rule that governs a yad. Anything that serves as a handle, whether to hold the food while eating it, to lift it, or to carry it from place to place, is joined to the food for the purposes of hilchos tumah. If the handle becomes tamei, the fruit becomes tamei along with it. And the reverse is equally true: should something tamei touch the fruit itself, the tumah spreads to the handle as well. The two are treated as a single unit in this respect.
That partnership, however, reaches no further. The mishnah's term eino mitztaref teaches that the handle is not counted alongside the edible flesh when we measure whether there is enough food present to pass tumah onward. Produce must have the bulk of an egg, a kabeitzah, before it can render another object tamei. Where the food by itself falls short of that bulk, and only the handle added to it would bring the total up to the mark, the produce still cannot transmit its tumah any further. The yad, then, is dragged into the tumah, but it never helps fill out the measure.
With this principle in place, the mishnah opens: "Eilu mitam'in u'metam'in v'ein mitztarfin", these become tamei and impart tumah, and they do not combine.
Roots of garlic, onions and leek
"Shoroshei hashum v'habetzalim v'hakerfeitos, bizman sheheim yeveishim": the roots of garlic, of onions and of leek, at the time that they are dry. Once these roots have dried out they no longer do anything to keep the vegetable from decaying, so they cannot be classified as a shomer. What remains is their usefulness as a place to take hold of the vegetable, and that makes them a yad, with all the consequences described above.
The stalk that is not aligned with the food
"V'ha'amud she'eino mechuvan k'neged ha'ochel": a vegetable will sometimes send up a stalk from its upper end. When that stalk rises straight out of the middle, standing directly over the edible flesh beneath it, it can be given the din of a shomer. When it instead sprouts off at an angle, to one side and not over the food at all, it guards nothing, and it belongs to the list before us as a handle and no more.
Handles on a cluster of grapes
The mishnah now turns to the various pieces of wood that come along with grapes. A grapevine has a branch, and off that branch grows the twig from which the cluster hangs.
"V'yad haparchil, tefach mikan v'tefach mikan": when the cluster is cut away, a section of the vine branch is deliberately left attached so that the cluster can be carried by it. This piece can run in two directions, forming a shape like the letter T at the top of the cluster's twig, with a tefach extending to either side. That much is still reckoned a handle.
"Yad ha'eshkol, kol shehu": as for the twig itself which bears the cluster, no matter how long it is it retains the status of a yad. The reason is straightforward: this is precisely how people handle grapes, lifting the bunch by the twig from which the clusters hang.
"V'zanav shel eshkol she'reikno": the lower portion of the cluster, once its grapes have been stripped away and it is empty, is also a place people take hold of, and it too is a yad.
The date branch
"V'yad hamachbeid shel temarah, arba'ah tefachim": when a branch of dates is detached from the date palm, one is left with a long stick from which the stems of the dates protrude. The stick serves as the handle for the dates growing at its end, and it carries the status of a yad up to four tefachim.
Stalks of grain
"V'kaneh shel shiboles, shloshah tefachim": the stalk of an ear of wheat and of other such grains and seeds is a yad up to three tefachim.
"V'yad kol haniktzarim, shloshah": with anything that is ordinarily harvested with a sickle, that is, grain of any variety, the handle is measured at three tefachim.
"She'ein darkan likatzer, yedeihem v'sharsheihem kol sheheim": and what of produce that is not customarily cut with a sickle but is instead pulled up out of the ground? There the roots that come up with it and the stalks attached to it count as a handle and an appendage of the produce whatever their length, even beyond three tefachim.
"U'malo'an shel shibolim": the fine hairs standing at the top of the ears of grain are at times used to grasp and pick them up, and so they too are included.
The summary
The mishnah signs off by repeating the words with which it began: "Harei eilu mitam'in u'metam'in", all of these contract tumah and convey it, "v'ein mitztarfin", and they are not reckoned together with the food. Every item catalogued here carries the din of a yad: it takes on tumah and passes it into the fruit, and in the other direction, when the fruit or the vegetable becomes tamei the handle turns tamei along with it. Yet not one of them is ever added to the produce to fill out the egg's bulk that must be present before other things can be rendered tamei.