Explanation of Plant Status Rankings

State Status

S1 1-5 occurrences in the state
S2 6-20 occurrences in the state
S3 21-100 occurrences in the state
S4 101-1000 occurrences in the state

RI Rare Plant Status (used only in RI)

SE — State Endangered.
Native species in imminent danger of extirpation from Rhode Island. In general, these species have 1 or 2 known or estimated total populations in the state. Plants listed as State Endangered are protected under the provisions of the Rhode Island State Endangered Species Act, Title 20 of the General Laws of the State of Rhode Island.

ST — State Threatened.
Native species which are likely to become State Endangered in the future if current trends in habitat loss or other detrimental factors remain unchanged. In general, these species have 3-5 known or estimated populations and are especially vulnerable to habitat loss.

SC — State Concern.
Native species not considered to be State Endangered or Threatened at the present time, but are listed due to various factors of rarity and/or vulnerability.

SH — State Historical.
Native species which have been documented for Rhode Island during the last 150 years but for which there are no extant populations.