Doctor Duck :

Your Cooperative Extension agent can help you if you get a sample . He can ID the plant or can have Bill Maley in Jackson or Marty Brunson at MSU help. Also one of the Florida { DNR ,Fish and Wildlife or Extension service} has an on line plant ID info with pic. I think the MSU cares pond Mgt. book references the Florida site. If this does not work post here and I can provide more info. Good luck. ewest