New York Natural Heritage Program
Doubtful Toad-rush
Juncus ambiguus Guss.
Monocots
Juncus ambiguus flowers and fruit Deborah Morrison
Family: Rush Family (Juncaceae)

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?
This rush is hard to distinguish from the closely related Juncus bufonius or toad rush and this difficulty is reflected in its species name.

State Ranking Justification [-]
There is one existing population that has not been surveyed in detail. There is also one historical locality.

Short-term Trends [-]

Long-term Trends [-]