Golden Purslane
Portulaca sativa means "cultivated" purslane and refers to a subspecies of purslane that has been bred to have a milder flavor that some describe as "nutty" and a most attractive color and texture. Commonly called Golden Purslane, this is the one I prefer when munching on a stalk raw right off the plant or in a salad. "Sativa" is the subspecies, so the alternate name would be Portulaca olerace sativa. At first it looks just like the other one, but as it gets bigger, it is easier to understand why they call it "golden" because when the light shines through them, the translucent leaves take on a lovely yellow-green glow.
Favored as a European pot herb in the Middle Ages, people on this continent have been tossing the tasty greens into pinto beans for centuries.