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

Hypocenomyce scalaris (Ach.) M. Choisy
Charcoal clamshell

Introduction to the Lichens

© Curtis Bjork  Email the photographer   (Photo ID #23996)

E-Flora BC Static Map
Distribution of Hypocenomyce scalaris
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Consortium of North American Lichen Herbaria map

Species Information

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Illustration By: Trevor Goward

Common Name: The Turtle Lichens. Describes the shell-like habit of the species. Minute stratified squamulose lichens, corticate above, corticate or not below, sorediate or not, squamules closely appressed or more often attached to substrate at one margin, the opposite margin weakly raised, short to subrotund, averaging to 0.8–1.5 (–2) mm wide, thin. Upper surface pale greyish, greenish or dark brown, shiny or not. Lower surface pale or darkening, lacking rhizines. Medulla white. Photobiont green.
Apothecia usually located along lobe margins, disc plane or occasionally convex, brown orblack; spores simple, ellipsoid to spindle-shaped, colourless, 8 per ascus.
Over (fire-blackened) trees.
Notes: Hypocenomyce is primarily a temperate and boreal genus consisting of ten species worldwide. Of the eight species reported for North America, four are known to occur in B.C. Hypocenomyce was formerly treated within Psora. The taxonomy of the western North American species has not been entirely elucidated; this treatment is preliminary, pending further study.
Species description:
Soredia present on lobe margins AND
Lobes concave to convex or, if helmet-shaped, then apparently never over oak; spores less than 14 m long, usually 1-septate AND
Lobes appressed to ascending, but rarely erect, averaging to slightly wider than long; soredia C+ red or C- AND
Upper surface never strong brown; apothecia, if present, black; soredia C+ red AND
Lobes larger, usually greenish, somewhat loosely attached (squamulose), averaging to more than 0.8 mm across; over deciduous trees and conifers; soredia K-
Cortex and soredia C+ red, KC+ red.
Lecanoric acid.

Source: Lichens of British Columbia

Habitat / Range

Habitat: Frequent over charred or uncharred bark or wood throughout
World Distribution: circumpolar, S to CA.

Source: Lichens of British Columbia

Synonyms and Alternate Names

Lecidea ostreata (Hoffm.) Schaerer
Lecidea scalaris (Ach. ex Lilj.) Ach.
Psora ostreata Hoffm.
Psora scalaris (Ach. ex Lilj.) Hook.

Taxonomic and Nomenclatural Links

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General References