Purslane

Leenda, Leenda! Weed-ho' and scientist that you are, surely you've met purslane with its fat red stems and succulent leaves. I'll bet you know the latin names of more than half the weeds you pull.

The best that can be said for purslane is that it's flat. (Would that that were a compliment in other walks of life.) As Dave points out, it is edible. But honestly, that's not as important as the fact that purslane's diminutive stature makes it a minimal threat to neighboring cultivated plants - at least in its youngest stage.

If you're keeping up with weeding every day or two (ha!) the tiniest seedlings can be done in with a light scraping of the surface of the soil with the back of your trowel. Larger plants, which no doubt abound after the second day must be traced to their center and the root carefully grasped and pulled.

Final warning. Don't leave the uprooted plants on the surface of the soil. Don't be fooled into thinking you can leave the dying plants to mulch your bare soil as you might with other weeds. Take them away. Far away. The succulent plant is able to flower and mature seeds long after you think you've left it gasping its last breath.