Zeh Keli V'Anveihu

The Mishna on daf 29b of Sukkah states that a lulav that is dried out is pasul. Rashi over there explains that the reason is because you need to fulfill "hidur mitzvah", to beautify the mitzvah, as it says "Zeh Keli V'Anveihu". Tosafos there asks two questions on Rashi. #1 The sugya on 11b speaks about the mitzvah of binding the lulav and the Gemara says that it is only a din l'chatchila and is not m'akev b'dieved. Now, we know that the source for binding the lulav is the general din of hidur mitzvah, which is learnt from the pasuk of zeh keli v'anveihu. If so it would seem from this gemara that zeh keli v'anveihu is only a din l'chatchila. This is difficult for Rashi because the Mishna says that a lulav that is dried out is totally pasul, even b'dieved. So how can Rashi say the source for this din is hiddur mitzvah if that is only a din l'chatchila? The second question that tosafos asks is that the sugya on 31a in sukkah says explicitly that the reason a dried out lulav is pasul is because lulav is compared to esrog and by esrog it says the word "hadar". So the real source is the pasuk of "hadar" and not hiddur mitzvah, which is learnt from the pasuk of zeh keli v'anvehu. These are the two questions that we will return to next time as we elaborate upon the din of zeh keli v'anvehu.