Birder20714:
Spiral Pondweed (Potamogeton spirillus) 08-21-2013 St. Mary's Lake, St. Mary's Co. MD 3
Birder20714:
Waterthread Pondweed (Potamogeton diversifolius Rafinesque) 07-05-2018 College of Southern Maryland--Prince Frederick, Calvert Co. MD 2