Daf Yomi - Sukkah 34- To tie the esrog or not

The Gemara derives from the word ulekachtem, and you shall take, that the four species are essential to each other, i.e. that one must have all four species available when he is prepared to fulfill the mitzvah. Nonetheless, one is not required to tie the esrog together with the other species, because the verse states the fruit of a hadar tree, (vekapos) the branches of date palms, and it does not state (kapos) and the branches. This teaches us that one is not required to tie the esrog together with the other three species. The Shulchan Aruch in Orach Chaim 651:11 rules that one must hold the esrog next to the lulav while waving the species and one must waive them all together. The Bikkurei Yaakov quotes the Taz who rules that if one ties the lulav together with the esrog, it is invalid because it is said regarding the lulav kapos and not vekapos. The Bikkurei Yaakov questions the words of the Taz, because our Gemara merely states that from the fact that the Torah did not write vekapos we derive that is not required to tie the esrog even according to the opinion that maintains that one is required to bundle the species. We maintain, however, that one is not biblically required to bundle the species at all, so why should bundling the esrog with the other species be forbidden? The Bikkurei Yaakov offers other proofs to his thesis and concludes that if one bundles the esrog with the other species, he has fulfilled the mitzvah.