There is a very important dispute between Maran and the Rama (Rabbi Moshe Isserles of Cracow, 1525-1572) regarding the qualifications of the Lulab, as recorded in the Shulhan Aruch (Orah Haim 645:3; listen to audio recording for precise citation). Each leaf of the Lulab actually consists of two leaves that are attached to one another. According to the Rama, if the top leaf of the Lulab is split, such that its two halves are detached from one another all the way down to the spine of the Lulab, then the Lulab is invalid for use. Even though all the other leaves of the Lulab are not split, a Lulab may not be used for the Misva if the top leaf is split all the way down to the spine. The Rama adds that it is customary and proper ("Misva Min Ha’mubhar") to ensure that the top leaf of the Lulab is not split at all. This is why we see many people carefully inspecting the tops of the Lulabim while choosing a Lulab for the holiday.
Maran, however, disagrees. He rules that a Lulab is disqualified only if the majority of its leaves are split. As long as most of the leaves are not split, the Lulab is valid even if the top leaf is split. According to Maran, the state of the top leaf of the Lulab does not itself determine the validity of the Lulab.
Surprisingly, Hacham Ovadia Yosef follows the stringent ruling of the Rama on this issue. Although some scholars questioned why Hacham Ovadia did not accept Maran’s position, the accepted practice is to follow the Rama’s ruling and to ensure that the top leaf of the Lulab is not split at all. It is therefore advisable to purchase a Lulab that has a brown substance at the top that holds the top leaf in place, thereby guaranteeing that it does not split, and one should be careful not to touch the top of the Lulab. Specifically, the Deri brand of Lulabim that are sold nowadays are sturdy and the tops are generally tightly closed, and one should try to purchase such a Lulab in order to ensure that the top leaf is not split at all. It should be noted that although a Lulab that is sealed at the top cannot be shaken, Sephardic custom does not require shaking ("Kishkush") the Lulab at all. Our practice is to perform the Na’anu’im (waving) by simply moving the Lulab back and forth, without shaking the Lulab. Only the Ashkenazim have the custom of gently shaking the Lulab as they perform the Na’anu’im. Thus, purchasing a Lulab that is sealed at the top does not interfere with the Na’anu’im.
Summary: If the top leaf of the Lulab is split all the way down to the spine of the Lulab, the Lulab is disqualified for use. It is proper to use a Lulab whose top leaf is not split at all, and it is therefore advisable to purchase a Lulab that has a brown substance at the top that holds the top leaf in place; the Deri brand of Lulab is especially recommended, as it generally satisfies this requirement.
