Havaas' Rocktripe Lichen - Umbilicaria havaasii
State Rank Reason (see State Rank above)
Known from a few locations in western Montana. Montana occurs on the eastern edge of this species range.
Thallus foliose, umbilicate, roundish to broadly and irregularly lobed, mostly less than 10 cm in diameter, rather fragile when dry; margins often perforate and lacerate; upper surface gray, gray brown, to blackish, partially grayish to white pruinose, especially on reticulate ridges near the umbilicus, the ridges fading radially, distinct or weak; lower surface light tan near umbilicus, dark gray brown toward the margins, with sooty black patches (from thalloconidia); sooty black rhizines often present, frequently in tufts, sometimes the tufts protruding upwards through holes in the surface; soredia and isidia lacking; apothecia rare (McCune and Geiser 2009)
U. havaasii can form fluffy colonies on rock, in contrast to the more appressed growth form of many Umbilicaria species. Up close, U. havaasii is distinctive in the combination of sooty black areas on the lower surface and subtle to distinct perforations near the lobe margins (McCune and Geiser 2009)
Arctic to Oregon, also occurring in the northern Rocky Mountains (McCune and Geiser 1997). Also occurs in Norway and Greenland (Thomson 1984).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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(Observations spanning multiple months or years are excluded from time charts)
On siliceous (noncalcareous) rock.
May reproduce sexually by spores from the apothecium.
Threats or Limiting Factors