Plants have a secret social life.
Apparently they can tell their siblings from plants not related to them, and in doing so compete against unrelated plants.
Wow, and I thought the neighborhood cats were interesting.

If you enjoyed that tidbit you'll go bonkers over the book The Secret Life of Plants. I'm about 1/2 way through & what a read. I'd been a gardener for about 35 years & had heard of some of the things that I'm realizing came from this book & were the result of some of the people quoted in this book. Here's a good source for some more info about it.. http://en.wikipedia.org/wiki/The_Secret_Life_of_Plants