When giving yourself a 2 block tall plant like a sunflower, they use the same block ID, 175. And the data value goes up to 5 (Peony). Giving yourself any 2 block tall plant with a data value greater than or equal to 6, Minecraft crashes.

java.lang.ArrayIndexOutOfBoundsException: 7
	at agu.a(SourceFile:149)
	at yn.b_(SourceFile:19)
	at zg.j(SourceFile:404)
	at zi.c(SourceFile:99)
	at bkn.a(SourceFile:124)
	at bkn.a(SourceFile:27)
	at bkc.a(SourceFile:215)