Below is information on Brittle Naiad from the NYSDEC Common Aquatic Species of NYS website:
Picture:G. Lovell, ADCNR, Bugwood.org
Leaves are opposite (in pairs along the stem), but sometimes appear to be in a whorl at the tip. Leaves are 1-2 inches long, toothed, stiff and pointed. Plant is very brittle and easily breaks into pieces.
Most abundant in the Hudson Valley and Central New York. It has also found its way into some Adirondack waters.