This is what the water hyacinth in the Palo Verde wetland currently looks like.  Seedlings existed throughout the wetland underwater, attached and rooted.  In areas where there has been high traffic (because of my work or because of cattle), the seedlings have release from the sediment and float.  When I first noticed them, they had two leaflets and a couple of roots, and I was unsure on their identification.  A week later and it is obvious.  The seedlings are generally smaller than a silver dollar.