The Gemara says that the Hadas branch can be identified since it has a fruit which tastes like the wood. But how do Chazal derive this from the verse "Anaf Etz Avos"? There is no mention of fruit there!
Ritva (c. 1300 Spain) changes the girsa: the defining feature is not fruit tasting like wood, but rather the branches cover the wood.
Rashash (19th century Lithuania): Read the word "anaf" as "anav", interchanging the pey with the beis, indicating that Hadas is the branch "anaf" which resembles the fruit "anav".
Aruch Laner (19th century Germany): Two explanations:
a) The word "avos" can mean thick-growing fruit, and thus the juxtaposition "etz avos" indicates that the wood tastes like the fruit.
b) Hekesh to esrog: Just like the "etz" used by "esrog" ("pri etz hadar") means the fruit and wood taste the same, so too should we understand the word "etz" used in reference to Hadas ("anaf etz avos").