I am now a big purslane fan and find it amusing I can now forage in my own plot. It comes from the family Portulacaceae, Genus Portulaca, species oleracea. In my garden, it is self-seeding and appears around July.
Of note, purslane contains more omega-3 than any other leafy veggie, thus cementing its status as the most perfect visitor. Wikipedia on purslane:
Purslane contains more omega-3 fatty acids (alpha-linolenic acid in particular) than any other leafy vegetable plant. Research published by Simopoulos states that Purslane has 0.01 mg/g of eicosapentaenoic acid (EPA). This is an extraordinary amount of EPA for a land-based vegetable source. EPA is an Omega-3 fatty acid found mostly in fish, some algae, and flax seeds. It also contains vitamins (mainly vitamin A, vitamin C, and some vitamin B and carotenoids), as well as dietary minerals, such as magnesium, calcium, potassium, and iron. Also present are two types of betalain alkaloid pigments, the reddish betacyanins (visible in the coloration of the stems) and the yellow betaxanthins (noticeable in the flowers and in the slight yellowish cast of the leaves). Both of these pigment types are potent antioxidants and have been found to have antimutagenic properties in laboratory studies. 100 Grams of fresh purslane leaves (about 1 cup) contain 300 to 400 mg of alpha-linolenic acid. One cup of cooked leaves contains 90 mg of calcium, 561 mg of potassium, and more than 2,000 IUs of vitamin A.The article also notes when collected early in the morning, it can be tangier due to something called CAM, which is an alternate type of metabolism that purslane turns to in arid conditions.
I am still trying to figure out recipes so if you have a favorite, please leave it in my comments. I eat it raw in yogurt but my favorite way, so far, is to saute it with lots of garlic and extra virgin olive oil and have it taco style or with rice.