A stolen lulav or a dry one is invalid.  [One] from an asherah or from a city that was led astray is invalid.  If its top was broken off, [or] its leaves severed, it is invalid.  If its leaves spread apart, it is valid. R’ Yehudah says: He should tie them together at the top.  The thorn palms of the Iron Mountain are valid.  A lulav that is three handbreadths long, [long] enough to wave, is valid.