New York Natural Heritage Program
Hill's Pondweed
Potamogeton hillii Morong
Monocots
Family: Pondweed Family (Potamogetonaceae)

State Protection: Threatened
listed species are those with: 1) 6 to fewer than 20 extant sites, or 2) 1,000 to fewer than 3,000 individuals, or 3) restricted to not less than 4 or more than 7 U.S.G.S. 7 minute topographical maps, or 4) listed as threatened by U.S. Department of Interior.

Federal Protection: Not Listed

State Rarity Rank: S2
A State Rarity Rank of S2 means: This plant is threatened/imperiled in New York because of rarity (typically 6-20 populations or few remaining individuals) or is vulnerable to extirpation from New York due to biological factors.

Global Rarity Rank: G3
A Global Rarity Rank of G3 means: This species is either rare and local throughout its range (21 to 100 occurrences), or found locally (even abundantly at some of its locations) in a restricted range (e.g. a single physiographic region), or is vulnerable to extinction throughout its range because of other factors.


Did you know?
This pondweed was first collected in New York in 1886 in Cayuga Lake near Ithaca but it has not been seen there since. The specific name honors the Reverend E.J. Hill who discovered it in Michigan in 1880. This plant is considered rare in every state/province where it is known.

State Ranking Justification [-]
There are 13 known populations of this globally rare plant in New York. There are three unverifed reports from the 1980s and about a dozen historical locations that need to be surveyed. This indicates that there are potentially up to twenty or more populations within New York State. Most of these populations are likely threatened to some degree from run-off, aquatic herbicide application, motor boat activities, or other activities that reduce water quality.

Short-term Trends [-]

Long-term Trends [-]