The Mishnah had taught: A dry Lulav is invalid.

Reasoning (R. Avin quoting R. Yehuda bar Pazi): The Pasuk states (Tehilim 115, 17), "the dead shall not praise Hash-m". (A dry Lulav is considered dead and not Hadar - 'beautiful' therefore not suitable to be used. The Torah requires the four species to be beautiful, as described in Vayikra 23,40.)

Beraisa quoting R. Yehuda: A dry Lulav is valid. (The requirement of Hadar only applies to the Esrog.)

R. Yehuda said to the Chachamim - In the coastal villages, they would give their Lulavs to their children as an inheritance!

Chachamim replied - One cannot learn from difficult times (when they had no other Lulavs available).

Query (asked to R. Avina): If its top middle leaf (Tiyomes) dried up (but its spine did not), what is the law? How is it different from a Lulav whose top was chopped off?

R. Avin: One (dried up) is Hadar and one is not Hadar (chopped, where its deficiency is visible to all).

R. Meloch quoting R. Yehoshua B"L: If the middle leaf was split, it is as if the leaves separated and it is invalid.

In identifiying the Lulav, the Pasuk says (Vayikra 23, 40), "Kapos Temarim" - "date-palm branches".

R. Tarfon: "Kapos (bound) Temarim" - the Lulav must be held together.

R. Akiva: Whether bound or not, the Pasuk still refers to it as "Kapos Temarim" (i.e. there is no need to tie it).

R. Yehuda: If the leaves are separated, he should tie it.

The following are Tzini branches of Barzel Mountain that are valid - if the top of one leaf reaches the bottom of the next (i.e. they overlap).

Beraisa: A 'Charus' (a palm branch that was left on the tree for two or three years becomes hard and opens up into many hard Lulavs that open in all directions) is invalid; if the palm branch only began to harden, it is valid.