Finger Ring Lichen
CR

Finger Ring Lichen

Arctoparmelia incurva

Unknown

Photo: Wikimedia Commons (CC) via https://en.wikipedia.org/wiki/Arctoparmelia_incurva

Overview

Arctoparmelia incurva is a species of saxicolous (rock-dwelling), foliose lichen in the family Parmeliaceae. First described in 1794 by Christiaan Hendrik Persoon, it has undergone several taxonomic reclassifications before being placed in its current genus in 1986. This yellowish-green lichen, characterised by its narrow, convex lobes and globular soralia, typically grows on sun-exposed siliceous rocks in alpine and arctic habitats.

It has a circumpolar distribution, found across North America, Europe, and parts of Asia. A. incurva can be distinguished from similar species by its specific morphological features and chemical spot test reactions.

The lichen is known to host several parasitic fungi and has shown tolerance to acid pollution.

Finger Ring Lichen (Arctoparmelia incurva) is critically endangered primarily due to its extremely limited distribution and vulnerability to habitat degradation. The species faces severe threats from air pollution, climate change, and human disturbance to its specialized rocky substrate habitats. Its slow growth rate and specific ecological requirements make recovery particularly challenging.

Threat summary

Habitat

Arctoparmelia incurva grows on sun-exposed siliceous rocks, and very rarely on wood. It is tolerant of acid pollution. It is widely distributed in Europe, where it has been recorded from 19 countries. In North America its range is mainly arctic, with records documented as far south as southern British Columbia and the Cascade Range. Researchers have also reported it in the Appalachians and the...

TERRESTRIAL· major

Other threatened species in Parmeliaceae

VU

Spotted Beard Lichen

Usnea glabrescens

Unknown
Iceland LichenCR

Iceland Lichen

Cetraria ericetorum

Unknown
Witches' Whiskers LichenVU

Witches' Whiskers Lichen

Usnea florida

Unknown
Salted Ruffle LichenVU

Salted Ruffle Lichen

Parmotrema crinitum

Unknown

Frequently asked questions

Why is Finger Ring Lichen classified as Critically Endangered?
Finger Ring Lichen is classified as Critically Endangered — facing an extremely high risk of extinction in the wild — because population sizes are very small, declining sharply, or restricted to a tiny range. Finger Ring Lichen (Arctoparmelia incurva) is critically endangered primarily due to its extremely limited distribution and vulnerability to habitat degradation. The species faces severe threats from air pollution, climate change, and human disturbance to its specialized rocky substrate habitats. Its slow growth rate and specific ecological requirements make recovery particularly challenging.
Where does Finger Ring Lichen live?
Finger Ring Lichen occurs in across multiple regions. Country-level distribution data is sourced from the IUCN Red List and cross-referenced with GBIF occurrences.
What are the main threats to Finger Ring Lichen?
The main threats to Finger Ring Lichen are ai-1, ai-2, ai-3, and ai-4. The full IUCN-classified threat record for this species is detailed on the species page.

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