SPECIES FACT SHEET
Common Name: skin lichen
Scientific Name: Leptogium platynum (Tuck.) Herre
Division: Ascomycota
Class: Ascomycetes
Order: Lecanorales
Family: Collemataceae
Technical Description: Thallus gelatinous foliose, 1-7 cm diameter, bluish
grey to brownish or blackish when dry, rubbery when wet. Upper and lower
surfaces with distinct cortices of a single layer of isodiametric cells, 5-9 µm
diameter. Hyphae of medulla loosely interwoven with long chains of cells of the
photobiont. Lobes round to elongate, 1-6 mm wide, 150-500 µm thick (in wet
cross-section mounted on slide), concave, with margins raised but extreme
edge of lobe down-turned so that each lobe is shaped like a rose petal; surface
of thallus with distinct narrow, wrinkles when dry; isidia absent but often with
small lobules on the surface; lower surface without an even covering of white
hairs, but attached to the substrate with tufts of white hairs. Apothecia
common and often abundant (Sierk 1964), on the lobe surface, 0.2-0.5 mm in
diameter, immersed or broadly attached, with a margin the same color as the
thallus, disc reddish brown. Spores 8 per ascus, large, 35-50 x 9-16 µm,
colorless, muriform, 7-9 septate transversely and 1-2 septate longitudinally.
Photosynthetic partner (photosymbiont) the cyanobacterium Nostoc.
Chemistry: all spot tests negative.
Distinctive characters: In Leptogium platynum, lobules on the lobe surface are
the most distinctive character, along with definite, fine wrinkles when dry. If
present, the large spores, 8 per ascus, distinguish it from some similar species.
Similar species: Leptogium polycarpum can grow among mosses on rock and
has immersed apothecia, but its wrinkles, when present, are short, irregular,
and tending towards bumpy, it has 4 spores per ascus, there are no lobules on
the surface and the thallus is thinner in cross-section (75-180 µm thick).
Leptogium californicum has sessile laminal apothecia, grows on rocks and soil,
can have distinct wrinkles on the surface, but is thinner in cross-section (70200 µm). Spores of L. californicum are 25-45 x 12-15 µm.
Other descriptions and illustrations: Brodo et al. (2001) (description and
good photo); McCune & Geiser (2009); Nash et al. (2004), Sierk (1964); photo
by Daphne Stone (see below).
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Life History: Details for Leptogium platynum are not documented. Distribution
is presumably by spores or fragments.
Range, Distribution, and Abundance: Western North America, Mexico, and
India. In North America, from British Columbia to California, Arizona, and
Texas.
National Forests: documented on Siuslaw NF, suspected on Olympic NF
because of similar habitat or proximity to known sites (Olympic NP). BLM
Districts: documented on Coos Bay and Eugene districts. Suspected on Salem
BLM district.
Habitat Associations: On soil or rock, usually near seeps or areas wet most of
the year.
Threats: Changes to the water table, road and trail construction or
maintenance, trampling by cattle.
Conservation Considerations: Search for new populations on federal and
state lands. Surveys in suitable habitat and protection of known sites should
be a priority.
Conservation rankings: Global: GU; National: NNR; Oregon Natural Heritage
Information Center: List 3 (S1S2).
Preparer: Daphne Stone, with edits from John A. Christy
Date Completed: March 2009
Final edits: Rob Huff, FS/BLM
June 2009
References:
Brodo, I.M, Sharnoff, S.D., & S. Sharnoff. 2001. Lichens of North America. Yale
University Press, New Haven and London. 795 pp.
Goward, T. 1995. Lichens of British Columbia: Rare Species and Priorities for
Inventory
http://www.for.gov.bc.ca/hfd/pubs/docs/Wp/Wp08.pdf.
Accessed 19 March 2009.
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McCune, B. & L. Geiser. 2009. Macrolichens of the Pacific Northwest, 2nd
Edition. Oregon State University Press. Corvallis, Oregon. 464 pp.
Nash, T. H., B. D. Ryan, P. Diederich, C. Gries and F. Bungartz. 2004. Lichen
Flora of the Greater Sonoran Desert Region, Vol 2. Lichens Unlimited,
Arizona State University, Tempe, AZ. 742 pp.
Oregon Natural Heritage Information Center. 2007. Nonvascular Plant
Rankings
2007.
http://oregonstate.edu/ornhic/documents/2007_t&e_book.pdf.
Accessed
28 February 2009.
Sierk, H.A. 1964. The genus Leptogium in North America north of Mexico.
The
Bryologist 67(3): 245-317.
Leptogium platynum showing lobules, apothecia, and strong wrinkles (lower
left).
Photo by Daphne Stone, 2009.
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