IUCN Red List Index

Find out more about the categories and criteria used to assess the conservation status of species in the IUCN Red List Index.

Extinct

When there is no reasonable doubt that there are no remaining individual plant species alive.

Extinct in the wild

When plant species are known only to survive in cultivation.

Amazon lily (Caliphruria tenera) is rated Critically Endangered (CR) and considered Possibly Extinct according to IUCN Red List criteria.

Critically Endangered

When a plant species has an extremely high risk of extinction in the wild or is already likely to be extinct, but for which confirmation is required. This could be based on:

A situation whereby a plant species has not been seen for over 50 years (so is thought to be extinct), but it is acknowledged that the habitat in which it resides is not well surveyed.
A data analysis showing the probability of a plant species being extinct in the wild is at least 50% within ten years or three generations.
A data analysis showing that a plant species is only found in an extremely small geographic area (e.g. less than 100 km²).
Evidence showing a total population size fewer than 50 mature individual plant species.

An example of a plant species included in this category is Dypsis brevicaulis.

Within the Critically Endangered category, it is often difficult to be certain that a plant species is extinct, as the last few individuals may still be holding on and in need of conservation attention for instance. Until a plant species can be confirmed extinct, conservationists can rate a species as Critically Endangered with the flag of ‘Possibly Extinct’. An example of a plant species included in this category is Amazon lily (Caliphruria tenera).

Agrostis trachychlaena - photo by Niek Gremmen

Agrostis trachychlaena occurs within an area of only 16 km² (the size of a large town) on two islands in the South Atlantic Ocean, and less than 250 mature individuals are thought to exist.

Endangered

When a plant species has a high risk of extinction in the wild. This could be based on:

A data analysis showing the probability of extinction in the wild is at least 20% within twenty years or five generations.
A data analysis showing that a plant species is only found in a small geographic area (e.g. less than 100 km² which is the size of inner city Paris).
Evidence showing a total population size fewer than 250 mature individuals.

An example of a plant species included in this category is bentgrass bentgrass (Agrostis trachychlaena).

The Eastern Cape giant cycad is widely distributed in the Eastern Cape and south-western KwaZulu-Natal, South Africa.

Vulnerable

When a plant species has a high risk of extinction in the wild. This could be based on:

A data analysis showing the probability of extinction in the wild is at least 10% within one hundred years.
A data analysis showing that a plant species is only found in a specific geographic area (e.g. less than 20,000 km²)
Evidence showing a total population size fewer than 1,000 mature individuals.

An example of a plant species included in this category is Eastern Cape giant cycad (Encephalartos altensteinii)

Tillandsia ionantha Marcelo Sellaro

Near Threatened

When a plant species is likely to become vulnerable in the near future. This includes:

When a plant species has been evaluated, but does not qualify for Critically Endangered, Endangered or Vulnerable now, but is likely to qualify for a threatened category in the near future.

An example of a plant species included in this category is blushing bride (Tillandsia ionantha).

Wood bitter-vetch is an erect herb related to the world-renowned broad bean (Vicia faba), and likewise a member of the pea and bean family (Leguminosae).

Least Concern

When a plant species is at low risk of endangerment and does not qualify for a threatened category or Near Threatened. Widespread and abundant plant species and groups are included in this category.

An example of a plant species included in this category is wood bitter-vetch (Vicia orobus).

Data Deficient

When there is not enough data about a plant species to make an assessment of its risk of extinction based on the plant species distribution and/or population.