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Montana Field Guide

Montana Field Guides

Mountain Oakmoss Lichen - Evernia divaricata

Potential Species of Concern
Native Species

Global Rank: G4G5
State Rank: S1S2
(see State Rank Reason below)

Agency Status
MNPS Threat Rank:

External Links

State Rank Reason (see State Rank above)
Populations have a very spotty distribution in Montana.
General Description
Thallus fruticose and pendulous to 30 cm long (lowland variant) or prostrate to 5 cm long (alpine variant). Thallus cream-yellow when fresh, turning reddish-brown in the herbarium; cortex frequently broken, exposing the medulla; medulla loose (lowland variant) or fairly dense (alpine variant); apothecia rare (lowland variant) or lacking (alpine variant) McCune and Geiser 2009. Chemistry: Cortex KC+ yellow; Medulla UV+ blue-white McCune and Geiser 2009.

Range Comments
Alpine Variant: Arctic-alpine south through the Rocky Mountains to Arizona and New Mexico (McCune and Geiser 2009). Lowland Variant: Rocky Mountains of British Columbia and Alberta south to New Mexico and Arizona (McCune and Geiser 2009).

Observations in Montana Natural Heritage Program Database
Number of Observations: 7

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

On trees in moist coniferous forests (lowland variant) or on alpine sod (alpine variant).

Both the alpine and lowland variants have been found in Montana.

Reproductive Characteristics
Fragmentation (?) and occasionally by spores from apothecia (lowland variant).

Threats or Limiting Factors
This lichen is a dispersal limited species.

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Citation for data on this website:
Mountain Oakmoss Lichen — Evernia divaricata.  Montana Field Guide.  .  Retrieved on , from