Mishna holds that a dry lulav is pasul,the gemara brings that rav yehudah holds a dry lulav is kosher.Now the mishna itself brought rav yehuda in the end saying that you must tie the lulav etc...So why wouln't he speak up in the mishna about a dry lulov being kosher?
Aaron Massry, deal,nj
Dear Aaron,
Your point is correct. However, it is not a question against the Mishnah. Sometimes, a Beraisa will add an opinion not mentioned in the Mishnah. Rebbi Yehudah is mentioned in the Mishnah on a different subject: Igud. But the Tana of the Mishnah chose not to mention him in the first section.
Note that the Ritva (31b, DH Tiyuvta) asks a similar question: If Rebbi Yehudah does not have a Derashah to invalidate missing Hadar, and he uses the word "Hadar" differently (31b), then in the Mishnah regarding Esrog (34b) he should argue and allow Chazazis, peeled, broken top, etc., but he is not mentioned there except with regard to the Pesul of dark green! The Ritva answers that Rebbi Yehudah does invalidate an Esrog not "fully-formed-correctly" and therefore agrees to invalidate the Pesulim in that Mishnah except for dryness, which he permits since it is fully formed. The Ritva seems to understand that since Rebbi Yehudah is mentioned in that section of the Mishnah, his opinion is not skipped and he then must agree to all Pesulim.
All the best,
Reuven Weiner