New York Natural Heritage Program
Water-thread Pondweed
Potamogeton diversifolius Raf.
Family: Pondweed Family (Potamogetonaceae)

State Protection: Endangered
listed species are those with: 1) 5 or fewer extant sites, or 2) fewer than 1,000 individuals, or 3) restricted to fewer than 4 U.S.G.S. 7 minute topographical maps, or 4) species listed as endangered by U.S. Department of Interior.

Federal Protection: Not Listed

State Rarity Rank: S1
A State Rarity Rank of S1 means: This plant is endangered/critically imperiled in New York because of extreme rarity (typically 5 or fewer populations or very few remaining individuals) or is extremely vulnerable to extirpation from New York due to biological factors.

Global Rarity Rank: G5
A Global Rarity Rank of G5 means: This species is demonstrably secure globally, though it may be quite rare in parts of its range, especially at the periphery.

Did you know?
The specific epithet diversifolius means diverse leaved (Fernald 1970). This is probably in reference to the differences in the submersed and floating leaves although, this character is shared by many other pondweed species.

State Ranking Justification [-]
There are 7 known extant populations and about 19 populations which have not been seen in recent years and are considered historical. Many of the specimens documenting these populations may be misidentified as this species has clearly been misunderstood in the past. This species is at the northern edge of its range in New York and many of its historical locations have probably been destroyed in the urbanized area of New York City.

Short-term Trends [-]

Long-term Trends [-]