A few days ago I naively asked Gulf Coast Ecosystems if they would ship me some Bryopsis cultures.  They noted that they do not normally stock it because it is highly invasive.  At first I thought they meant that it was highly invasive in fishtanks, but then it dawned on me that they meant that it was highly invasive to local waterways.  I certainly do not want to be responsible for messing up the local ecosystem, but I may have inadvertently done that had I not been informed by a responsible seller.  +1 Gulf Coast Ecosystems, +1.