As part of its north-south movement following introduction to Canada, Hydrocharis morsus-ranae L. (Hydrocharitaceae) has recently become established in slow-moving waters of the Champlain/Adirondack region of the northeastern US. The species is present on both the New York and Vermont shores of Lake Champlain and, so far, at a single location in the interior of the Adirondack Park. The southernmost Champlain/Adirondack occurrence is in the Champlain Canal south of Whitehall, NY (L. Eichler, Darrin Freshwater Institute, pers. comm.), within 25 miles of the Hudson River watershed—a population first recorded around 2006. Entry into the Hudson watershed, whether from the canal or Adirondack headwaters, has the potential to increase the spread of European frogbit well beyond the handful of spot occurrences currently recorded in the rest of the Northeast. The objective of this note is to summarize findings derived from recent student-driven research conducted on the status and biology of H. morsus-ranae in the Champlain/Adirondack region.
Martine, Chris; Langdon, Stephen; Shearman, Timothy; Binggeli, Casey; and Mihuc, Timothy B.. "European Frogbit (Hydrocharis morsus-ranae) in the Champlain/Adirondack Region: Recent Inferences." Rhodora 117, no. 972 (2015) : 499-504.