Lepraria barbatica Lendemer
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Authority
Lendemer, James C. 2010. Notes on Lepraria s.l. (Lecanoromycetes, Ascomycota) in North America: New species, new reports, and preliminary keys. Brittonia. 62 (3): 267-292.
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Family
Stereocaulaceae
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Scientific Name
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Description
Description - Thallus crustose, leprose, without "lobes," diffuse, patchy to confluent and continuous, with granules initially sparsely distributed, eventually accumulating in overlapping heaps that become confluent to form a thin continuous crust (0.2 -0.3 mm thick), light greenish -white in color; hypothallus a thin network of hyphae underneath the granules and extending outward from teh edge of the thallus; hyphae anchoring the granules to each other and to the substrate, 2.0-4.0 µm wide, hyaline, distinctly septate, branching frequently at the septa, thin walled, obscured by a layer of crystals that dissolve in KOH; rhizohyphae absent; granules medium in size, (20-)25-30(-50) µm in diameter, ecorticate, round, usually a single layer of hyphae surrounding an algal core consisting of a variable number of photobiont cells, readily dividing; photobiont green, coccoid, cells globose, (9-) 12-15 µm in diameter. Chemistry.- TLC and HPLC: Barbatic acid (major), usnic acid (minor). Spot tests: K-, KC+ yellow-orange, C+ yellowish- orange, P-, UV+ blue-white.
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Discussion
Etymology. - The specific epithet barbatica denotes the unusual chemistry of the species
Ecology and distribution. - Lepraria bar- batica is presently known only from the type locality where it occurred on sandstone in a cool overhang of a massive bluff overlooking a small artificial lake. The crustose lichens of the southern Ozarks and adjacent regions of the coastal plain are not well known and several endemics have recently been described from the region (Harris & Ladd, 2007). It is likely the absence of additional records is due to collection bias.
Discussion. - The combination of usnic and barbatic acids in a crustose lichen with a green algal photobiont is relatively unusual and has never previously been reported from Lepraria (Saag et al., 2009). The only chemically similar species is L. methylbarbatica Elix which was described by Elix and Kalb (2008) from Queensland. That species lacks usnic acid and produces barbatic acid only as a trace acces- sory to methyl barbatate which is the major substance. I have chosen to describe L. barbatica in the hope that additional collec- tions will be uncovered so that its morphology and ecology can be fully evaluated.