When: 2009-01-30

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

Who: Chris Parrish (kitparrish)

Specimen available

Location: 35°13’49.26"N 85°57’47.14"W, el. 575 m. Dotson Point Trail.

Substrate: This is one of the most abundant lichens on exposed horizontal surfaces of sandstone rocks and bluffs in this area of the western escarpment of the Cumberland Plateau.

Habitat: Rich, oak-dominated, eastern deciduous hardwood forest.

Dotson Point Trail, 30 Jan 2009: 35391-35395
Dotson Point Trail, 12 Mar 2009: 39006-39021

cortex C-, K-, KC+ indeterminate dirty yellow
medulla C-, K-, KC+ pink immediately, fading fast

Characterization: saxicolous yellowish green shield lichen with
(1) characteristic “advancing wave” pattern in shades of yellowish green
(2) crowded isidia (“pustules resembling isidia,” Brodo, p.138) in center of thallus and along radial ridges and folds;
(3) occasional laminar black pycnidia and small, cup-like, raised apothecia(?) with whitish margins;
(4) jet black undersurface; tan under outermost marginal lobes;
(5) firmly appressed, but can be removed largely intact with patience

Voucher specimen: Tennessee, Franklin County, Sewanee, Dotson Point Trail, 12 Mar 2009, Chris Parrish 0005, det. Gary Perlmutter (NCU)

Common name: rock greenshield lichen

Species Lists


Dotson Point Trail, 30 Jan 2009
Dotson Point Trail, 30 Jan 2009
Dotson Point Trail, 30 Jan 2009
Dotson Point Trail, 30 Jan 2009
Dotson Point Trail, 30 Jan 2009
“pustules resembling isidia,” 7.1x
“pustules resembling isidia,” 12.5x
“pustules resembling isidia,” 16x
“pustules resembling isidia,” 20x
“pustules resembling isidia,” 20x
“pustules resembling isidia,” 32x
pustules and pycnidia, 12.5x
pustules and apothecia (?), 32x
apothecia (?), 40x
maculae, 16x
pycnidia, 63x
pycnidia, 115x
undersurface, 12.5x
undersurface, 25x
undersurface, 25x
undersurface, 50x

Proposed Names

28% (1)
Used references: Brodo, Sharnoff, and Sharnoff, pp.733-742 and Xanthoparmelia images on MO
57% (1)
Used references: Brodo, Sharnoff, Sharnoff, pp.316-317

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= Observer’s choice
= Current consensus


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