My earliest memory of this particular weed is from my primary school days when we use to call them "surings" - an Afrikaans name that I've always believed was derived from the fact that they are sour to the taste. As school kids we used to munch on the stem of the "suring" flowers during lunch breaks, precisely because they were a little sour. Quite tasty in fact.
Just before you get the wrong idea - no, my mom packed in yummy chicken and mayo, peanut butter and syrup, or toasted cheese and tomato sandwiches every day. The "surings" were just a treat on the side. ;)