shortest plant life cycle

[Ken Kinman]

As far as I know the shortest life cycle (about five weeks) belongs to Brassica rapa, but that is due to intensive selective breeding at the University of Wisconsin over the years.
     Perhaps a more interesting question is which angiosperm has the shortest life cycle under natural conditions (i.e., non-domesticated).  Maybe that is what John is asking about?
              ----- Cheers,   Ken