When: 2008-12-08

Collection location: Sewanee, Franklin Co., Tennessee, USA [Click for map]

Who: Chris Parrish (kitparrish)

No specimen available

Location: 35°13’2.86"N, 85°57’36.98"W, el. 545 m. Thumping Dick Cove.

Substrate and habitat: This lichen is growing on exposed sandstone at the rim of the western escarpment of the Cumberland Plateau in a floristically rich oak-hickory woodland.

Most of the black, button-like apothecia touch an edge of an areole. This photo seems a good match for the photo of Buellia spuria in Brodo, Sharnoff, and Sharnoff, p.188, but they mention that there is a similar looking species with a different chemistry. This photo also resembles that of Porpidia albocaerulescens in Brodo, Sharnoff, and Sharnoff, p.584. Like Porpidia, this example is growing on siliceous rocks (the local sandstone is reported to be 98% quartz) and it is showing an orange stain perhaps due to iron in the substrate.

Sharnoff’s Porpidia albocaerulescens gallery
CNALH images and locality map, and a larger, interactive locality map.

Common name: smoky-eye boulder lichen

Species Lists


Proposed Names

13% (2)
Used references: Brodo-Sharnoff-Sharnoff, p.188.
46% (1)
Recognized by sight: image is of saxicolous crust with pruinose apothecia

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= Observer’s choice
= Current consensus


Add Comment
needs microscopy
By: Gary Perlmutter (gbperlmutter)
2009-03-05 19:34:59 CST (-0500)

The image of this crust could be a buellia, or a whole host of similar-looking taxa. The apothecia appear pruinose, which suggests Porpidia albocaerulescens, a very common saxicolous crust in shady environments (at least in North Carolina). You need to collect a specimen, dissect it’s apothecia and examine the internal structures under a compound microscope using keys available, including Brodo et al.’s Lichens of North America or Harris & Ladd (2005) Ozark Lichens.