Forensic Botany

One thing I tell police frequently is this: If you get a call of somebody breaking into a house, and you see somebody walking down the street as you pull up, as you question him, ask to see the cuffs of his pants. If he's climbed through a hedge or walked through a yard--most people have weeds around. Weeds get around in lots of clever ways; they often have little sticky parts that adhere to you shoes, or your shoelaces, or your pants cuffs, or they land in a pants cuff. If the suspect says, "Oh, I got those in my grandmother's yard," those particular weeds may not be there. So we've hooked people to certain crime sites though what kind of weeds have gotten stuck to them. Almost no one can lie about plant evidence.

Forensic botanist, in Crime Scene by Connie Fletcher, 2006