The mishna[1] states explicitly that when the pitam is removed, the etrog is pasul, whereas when the oketz is removed, the etrog is still kosher. The simple explanation for this distinction is that the pitam is a more integral part of the etrog fruit than the oketz is. Therefore, it is specifically when the pitam has been removed that the etrog is considered incomplete (chasser), which makes it pasul (unfit)[2] on the first day of Sukkot.[3] Alternatively, some maintain that an etrog without a pitam is not considered hadar (aesthetically pleasing); if so, such an etrog is disqualified throughout Sukkot.[4]
Nevertheless, matters are not as simple as they initially seem. First, we must ask what exactly the mishna means in referring to the pitam. The gemara[5] describes the pitam as a buchna (pestle). Most opinions identify the pitam as what botanists call the citron’s “style” – i.e., the thin protrusion at the top of the fruit, which is usually the same color as the fruit itself. At the end of the pitam is a brown, crown-looking piece known as the shoshanta (stigma). On the opposite side of the etrog, what we generally call the oketz, is simply that which happens to remain of the stem when the fruit is cut off from the tree. It is certainly logical to assume that the pitam, in this description, is more a part of the fruit than the oketz, and it is therefore logical to require only the pitam to be intact.
However, not all Rishonim agree with the above identification of the etrog’s parts. Some say that the mishna’s pitam and oketz are both on the side of the etrog’s stem, i.e., the side where the fruit is connected to the tree.[6] According to this opinion, the pitam is the part of the stem that extends into the indentation at the bottom of the fruit. If this part of the stem is missing, the etrog is pasul. The oketz, in this view, is the part of the stem that is somewhat removed from the fruit, and specifically this part of the stem does not need be intact in order for the etrog to be kosher. The Tur[7] understands that according to this approach, if the part of the fruit that we call the pitam is missing, the etrog is still kosher. The apparent logic is that the “style” is not an integral part of the fruit, as it extends beyond the fruit’s fleshy section. In contrast, if the stem were to be completely removed, this would leave a hole in the surface area of the fruit itself.
The Rambam[8] is among those who hold that if either what we call the pitam (the “style”) or what we call the oketz (the entire stem) is severed, the etrog is pasul. The case in which the etrog is kosher is when only some of the oketz is lost but enough remains for there not to be an indentation in the etrog itself. Most authorities understand that according to the Rambam, the loss of only the shoshanta does not disqualify the etrog, whereas if some of the more stick-like base of the pitam is missing, the etrog is invalid.[9]
In terms of the practical halacha, the basic ruling is that a missing shoshanta does not disqualify the etrog, although the Rama[10] comments that it is preferable to avoid using an etrog whose shoshanta fell off. The Shulchan Aruch[11] rules that a missing pitam disqualifies an etrog, but he does not provide specifics. The Mishna Berura[12] does not clearly decide between the differing opinions regarding the case in which only part of the pitam is broken off, such that enough remains for the top of the fruit to be whole without any indentation. If part of the remaining pitam protrudes beyond the fruit, it is likely kosher. Regarding the oketz, enough of the stem must remain to cover the indentation.[13]
The Rama[14] points out that if the etrog never had a pitam, it is kosher, and he adds that this was, in fact, the most common situation in his time. In truth, an etrog always starts off with a pitam, but the pitam often dries up and falls off in the course of the etrog’s growth due to the effects of sunlight or other factors. The Rama’s leniency applies at least to a case in which the pitam falls off at an early stage and the fruit continues to grow naturally without it. The halacha is less clear regarding cases in which the pitam fell off at a relatively late stage on the tree. If a light-color scab is found in place of the pitam, it suffices as a sign that the pitam did not fall off problematically late.[15] If certification indicates that the etrog came without a pitam, then one may assume that certifiers checked the etrog and determined that it convincingly appears that the pitam fell off early enough.
Why do people express concern regarding a broken pitam and not regarding a missing oketz? It is probably because it is much more common for some or all of the thin, protruding pitam to fall off than for the relatively sturdy oketz to do so.