Diagnosis: Similar to Lepraria methylbarbatica but differs in containing zeorin and 4,5-dichlorolichexanthone and in growing on corticolous substrata.

Holotype:—Ecuador. Galapagos: Floreana island, caldera of Cerro Pajas, trail at the end of road leading up to crater rim, 1˚17’47” S, 90˚27’23.19” W, on branch of Zanthoxylum fagara, 02-Jan-2010, Hillmann, G. GAL-10 (CDS 44773).

Thallus corticolous; placodioid leprose, i.e., developing upon a common, shared hypothallus, delimited by a byssoid arachnoid, ‘cottony’prothallus forming an irregular margin, not lobed or ‘crisped’ (finkii-type sensu Lendemer 2011a); surface greenish gray to bluish green, in the herbarium fading to a pale yellowish green; hypothallus moderately to well developed, loose, ‘fluffy’, ‘cottony’; rhizohyphae sparse or absent; granules ecorticate, ill-defined, farinose [(25–)40–60(–70) µm in diam., rather fine and relatively uniform in size], generally loosely packed, typically with some protruding hyphae; photobiont green, coccoid, 6–12 μm in diam.

Spot tests and chemistry: P-, K± sordid yellow, KC-, C-; UV+ deeply ochraceous; zeorin, methyl barbatate, 4,5-dichlorolichexanthone, unknown terpenes (possibly from the bark substrate).

Etymology: This species is named in honor of American lichenologist James Lendemer, in recognition of his contributions to our knowledge of the genus Lepraria.

Distribution and ecology: This new species in known only from the Galapagos where it occurs on both native and introduced trees in the agricultural areas of the humid zone on the inhabited islands, Santa Cruz and Floreana.

Notes: Chemically and morphologically this new species resembles the Australian Lepraria methylbarbatica Elix (in Elix & Kalb 2008: 31) and the North American endemic L. barbatica Lendemer (2010a: 273). Lepraria barbatica contains barbatic acid, a substance chemically related to methyl barbatate present in both L. lendemeri and L. methylbarbatica. However, L. barbatica contains usnic acid in addition to barbatic acid, so is chemically distinct from both L. lendemeri and L. methylbarbatica. Lepraria lendemeri, like L methylbarbatica contains methyl barbatate as its major metabolite, but the Australian species is invariably saxicolous and lacks both zeorin and 4,5-dichlorolichexanthone. Instead, L. methylbarbatica contains minor or trace quantities of barbatic acid and methyl 2’-O-methylbarbatate, substances not observed in L. lendemeri.

Methyl barbatate, the characteristic metabolite of these species may previously have been overlooked or even mistaken for the very common lichen substance, atranorin. It exhibits an Rf somewhat higher than atranorin: in solvent C at Rf 86, in solvent A only slightly above atranorin, at Rf 77. It forms a dull, barely visible spot in long wave UV-light (λ 365 nm) and appears as distinct dark spot in short wave UV-light (λ 254 nm) before charring. After H₂SO₄ and heat (‘charring’) the spot becomes pale grey, or, depending on concentration, may be even pale to deep yellow, then usually with a pale gray halo. In long wave UV-light (λ 365 nm) after charring this spot appears gray to almost bluish or, again depending on concentration, purplish gray with a bright greenish halo.

Specimens examined (paratypes). Ecuador. Galapagos: Santa Cruz Island, Bellavista, near parking place for trail to Media Luna, 0˚40’10” S, 90˚19’22” W, 400 m alt., on Cinchona, 27-May-2005, Aptroot, A. 63130 (CDS 29860); tras del Puntudo, ex finca de Don Benito, 0˚38’27.10” S, 90˚19’59.39” W, 732 m alt., on Cordia alliodora, 07-Jul-2006, Nugra, F. 47 (CDS 32700).