Purslane has a good flavor, is nutritious, and is one of the most common edible weeds. Scientific name is Portulaca Oleracea. There is a similar plant, Portulaca Grandiflora which has a bad aftertaste, but it looks very similar to purslane.
Purslane - Weed It or Eat It? - The Homeowners Column - University of Illinois Extension serving Champaign, Ford, Iroquois and Vermilion Counties http://buff.ly/1uHF8Ql