As I am helping someone these weeks, I am spending a lot of time in cars, commuting, and if you spend a lot of time in cars, you spend a lot of time in parking lots. The best thing about parking lots for an ecologist is that you get lots of time to commune with weeds. Almost every parking lot has some tiny unpaved fraction that nature has been able to invade, and they are always weeds. Weeds are perhaps my favourite plants, probably in a perverse way because they are so human -- ubiquitous, trashy, fast invaders, stubborn, and great replicators. Weeds are merely plants that get in the way of what human beings want, and one of the reasons no one wants them is that they are mimics -- many varieties are designed to take advantage of the cultivated originals by becoming so similar that it requires a lot of work and decision-making to pull them up. In this way weedy grasses and fake Gucci bags are identical. Cover versions of songs, tribute albums, and orchestral versions of Beatle tunes are the weeds of the music world. Chicken chow mein is the weed of Chinese food. But that is to denigrate the great dignity of the "original" weeds: nothing is more uplifting on a sunny spring day sitting in a parking lot waiting for someone than to see a flock of dandelions hard at work in some messed up corner.