Purslane is really high in Omega-3 fatty acids too! As far as I know there is nothing poisonous that is similar to purslane. In fact Wildman Steve Brill considers purslane to be one of the easiest wild plants to ID. ‘Keying out’ (the process of following a taxonomic key) might give you the confidence to chow down. The University of Illinois has a simple key that filters out the possible plant choices as you answer the questions. Answer what questions you can on the left and you should end up with Purslane as the only (or one of the only) plants left on the right.