Notes: Location: 35°12’48.33"N, 85°54’14.26"W, el. 524 m. Piney Point.

Substrate: Growing on exposed sloping and vertical surfaces of bare sandstone rim-rock at the edge of the western escarpment of the Cumberland Plateau.

Habitat: Pine dominates the rim of the canyon, and oak and other deciduous hardwoods cover the plateau behind that and in the canyon below.

The lichens in these photos are damp. They quickly dry to an indeterminate pale gray-brown, closely matching the color of the rocks they are growing on.

Note added on 21 feb 2009: Thanks, Noah. Brodo notes that Lasallia is related to Umbilicaria, but “only Lasallia … has pustules or warts with corresponding depressions on the lower surface,” and that was evident in this specimen because the blister-like depressions in the thallus were quite deep, and even vertical-sided, and the thallus was so thin, even floppy when moist. So this is Lasallia papulosa, and not Umbilicaria.

On p.366, Brodo explains the prominent reddish color noticeable in several of these pictures as well. “Apothecia black, lecideine, sometimes with a reddish pruina …. pruina K+ purple (anthraquinones).” I recorded in my notes “medula C+r, K-; apothecia K+ wine red,” so it was the pruina producing the K+ reaction.

References:
Sharnoff’s Lasallia papulosa gallery
CNALH images and locality map, and a larger, interactive locality map.

Voucher specimen: Tennessee, Franklin County, Sewanee, Sewanee-St.Andrew’s Trail, 17 Mar 2009, Chris Parrish 0014, det. Gary Perlmutter (NCU)

Common name: common toadskin