a bed of nails. bricks. potatoe chip bags.
Is it not yet obvious?! or you are just making a fool question out of it?! Of course no as if of you are best friends, hahaha! Who can sleep on a plants who's full of torns? lol!
You answered your own question when you stated "what else couldn't you sleep on?"
You can sleep on a cactus, I just don't see why you would want to.