This is actually an un-fact, but it is such a cool story that it is worthy of inclusion.
The Mandrake plant has a bit of a chequered past, and it is partly due to the way in which the roots of the plant can end up, in the eyes of some, looking like humans. This has led to some stories surrounding the growth of the plant that are even stranger than the roots themselves.
The legend that surrounds the Mandrake plant is that it would only grow on land where either the fat, blood, or semen of a man that had been hanged would drip down, and that is a pretty macabre thought. It would often be seen in a graveyard as well, which is why it has developed a reputation of being linked to the dead.
Of course, it has nothing whatsoever to do with this although you must admit that the idea is different and it is certainly good enough to freak out some people as it just sounds as if it has enough truth about it.