Purslane (Portulaca oleracea) is a fleshy succulent, preferring to grow in hot, dry weather. It has a low growth habit and produces thousands of tiny seeds all summer long, giving it its reputation as a noxious weed. It can be hard to eradicate from your garden. However, it is also a prime edible, with a crunchy texture and wonderful flavor. While the flavor is sort of generically "green," some of them, usually the bigger leaves, have a distinct lemon flavor. In addition, they are one of the highest known vegetative sources of omega-3 fatty acids. It is also full of vitamins and minerals. Its dietary benefits are enough that some have gone so far as to call it a superfood.
So where can you get some seeds from this wonderful plant? I have yet to see any offered at seed catalogs, but it is pretty easy to score a little seed factory in many areas. Purslane uses its fleshy stems, which are also edible, as a water and nutrient storage device. After you have pulled the weed, it will continue to produce flowers and manufacture seeds as long as it can. I pulled one particularly healthy plant a few months ago. It was still producing flowers after a month of sitting in the sun. In Arizona. In July. So find the biggest plant you can find and pluck it. Then put it wherever you want the plants to take over. It will likely produce hundreds of seeds before it perishes. Unless the javelinas eat it first
Now go eat your weeds.