Potamogeton hillii, common name Hill's pondweed, is a species of plant found in North America. It is listed as endangered in Connecticut,"Connecticut's Endangered, Threatened and Special Concern Species 2015". State of Connecticut Department of Energy and Environmental Protection Bureau of Natural Resources. Retrieved 17 January 2018. (Note: This list is newer than the one used by plants.usda.gov and is more up-to-date.) Ohio, and Pennsylvania. It is listed as a special concern in Massachusetts and as threatened in Michigan and New York (state).
Commonly found in alkaline waters, Hill's pondweed has a narrow distribution from Wisconsin to western New England (Connecticut, Massachusetts and Vermont).
Description The leaves of Potamogeton hillii tend to be around 20–60 mm, all of which are submerged underwater. The fruit is fleshy and dry but does not split open when ripe. The fruit is also 2.3–4 mm in length and 2–3.2 mm in width. The flower blooms in mid-July through August, fruiting late-July through August.
History Hill's pondweed was first collected in New York in 1886 in Cayuga Lake near Ithaca. The name honors the Reverend E.J. Hill who discovered it in Michigan in 1880.
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