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Montana Field Guide

Montana Field Guides

Pustulate Tarpaper Lichen - Collema curtisporum

Species of Concern
Native Species

Global Rank: G3
State Rank: S1
(see State Rank Reason below)

Agency Status
MNPS Threat Rank:

External Links

State Rank Reason (see State Rank above)
In Montana this lichen occurs in a few locations and is not always present where habitat appears to be suitable.
General Description
Thallus foliose, to 2(4) cm broad, black, gelatinous when wet, with broadly rounded lobes; isidia and soredia lacking; spores 4-septate, hyaline, 20-40 by 3-4.5 microns, with blunt ends, straight or curved; apothecia generally present McCune and Geiser 2009. Chemistry: Spot tests are negative McCune and Geiser 2009.

Species Range
Montana Range


Range Comments
Eastern Washington, northern Idaho, western Montana, and northeastern Oregon (McCune and Geiser 1997); also reported from Sweden. In Montana it has been found on both sides of the Continental Divide, mostly between 900 and 100 meters.

Observations in Montana Natural Heritage Program Database
Number of Observations: 33

(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)

Habitat: Moist riparian forests, often in narrow sheltered valleys. Substate: Trunk (bark) of Populus trichocarpa; occasionally on conifer twigs.

Reproductive Characteristics
Reproduces sexually by spores from the apothecium.

Threats or Limiting Factors
None identified.

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Citation for data on this website:
Pustulate Tarpaper Lichen — Collema curtisporum.  Montana Field Guide.  .  Retrieved on , from