Here's a nice little gem that I've known about for a while. Earlier tonight (more like just now) I just remembered that it existed. It allows for procedural generation of plants. That's right... PLANTS!
Go here for the registration information. The program is free:
The software itself dates back to 2002, but it's still very useful, even for an old piece of software. It's windows only and not in development any more. But I'm sure the linux fellows can use WINE.
And no, I can't be assed to edit my procedural program thread and add it to it. Someone else can do that for me.