E-Flora BC: Electronic Atlas of the Flora of British Columbia

Collema tenax (Swartz) Ach.
Tarred tarpaper


Introduction to the Lichens
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E-Flora BC Static Map
Distribution of Collema tenax
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Consortium of North American Lichen Herbaria map

Species Information

General:
Common Name: The Tarpaper Lichens. Stresses the blackish nonstratified medulla that becomes somewhat swollen, translucent and jellylike when moistened.
Minute to occasionally large nonstratified foliose lichens (gelatinous when wet), lacking true cortex, (except cortex present on apothecial margin: see below) isidiate or not, lobes closely appressed to semi-erect, 0.5–10 (–15) mm wide, thin to thick. Upper surface dark olive brownish or blackish (ours), dull. Lower surface dark, rhizines absent or rarely present. Medulla absent. Photobiont blue-green.
Apothecia located over upper surface or marginal, with thalline margin, disc reddish brown; spores 2- to multicelled, ellipsoid to needle-shaped/acicular, (4–) 8 per ascus. Over bark, earth and rock, usually base-rich.
Notes: Collema is a taxonomically difficult genus comprising about 80 species, of which 35 are known to occur in North America and 20 in B.C. Chemistry is of no diagnostic value in this genus. Two keys are provided. The first key emphasizes macroscopic vegetative characters, though spore characters have been incorporated in some places. The second key, to nonisidiate species, stresses spore characters and is more technical.
Comments:
Some (reduced) forms of Heppia lutosa are superficially similar, but have single-celled spores, differing from the usually 4-celled spores in C. tenax. Three varieties of C. tenax are reported to occur in B.C.

Source: Lichens of British Columbia

Habitat / Range

Habitat: Frequent over (recently disturbed) base-rich soil in open inland localities, especially in arid climates
World Distribution: circumpolar, S to CA, NM.

Source: Lichens of British Columbia

Synonyms and Alternate Names

Collema cristatellum Tuck.
Collema pulposum (Bernh.) Ach.

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