Type: Ecuador. Galapagos: Floreana, lava flow near the shore just north of Black Beach, on Bursera graveolens, 24-Apr-1976, Weber, W.A. s.n. & Lanier, J. (L-62983, COLO 294539–holotype!).
Description.Thallus corticolous, thin to moderately thickened, rimose to rimose-areolate, areoles granular to densely verrucose or bullate; surface white to pale gray, roughened, matt, epruinose or with very faint, whitish pruina, lacking soredia; prothallus faintly developed, powdery arachnoid to compact, generally white, but occasionally blackening and often forming a line where different thalli meet. Apothecia numerous, often densely aggregated, circular to slightly irregular in outline, often deformed by mutual pressure, 0.4–1.4 mm in diam., adnate to soon sessile and then ±constricted, distinctly lecanorine with a persistent, entire to weakly undulating, smooth, crenate or strongly verruculose, epruinose to weakly whitish pruinose margin, concolorous with the thallus; disc plane to ±convex, deep mahogany brown, epruinose to faintly whitish pruinose; hymenium hyaline, not inspersed; epihymenium with crystals, with a diffuse reddish brown pigment (arnoldiana-brown: K+ dull brown, HCl+ reddish brown, N−), crystals dissolving in K, pigment persistent (pulicaris-type); properexciple thin, indistinct, with abundant small crystals dissolving in K; thallineexciple thick, distinctly corticate, with many small crystals that obscure few larger ones, often visible only when the small crystals are dissolved in K, but the large ones persist (melacarpella-type); hypothecium hyaline; ascospores 8/ascus, simple, ellipsoid to broadly ellipsoid, (8.9)–9.6–11.3–(11.9) × (5.9–)6.5–7.1(–6.9) μm (n = 45). Pycnidia not seen.
Chemistry. Thallus cortex including apothecial margin P+ yellow, C−, KC−, K+ yellow; with atranorin [major], 20α-acetoxyzeorin [major]; [specimens analyzed with TLC: Herre, A.W.C.T. 57 (L-41173, COLO 195077; Bungartz, F. 7674 (CDS 38177)].
Ecology and distribution. Endemic to the Galapagos (Guderley 1999); a common species throughout the dry and lower transition zone, rarely also found in the humid zone and few collections from the high altitude dry zone, on bark of native and endemic trees and shrubs (Bursera, Clerodendrummolle, Crotonscouleri, Piscidiacarthagenensis, Psidiumgalapageium, Scalesiamicrocephala).
Notes. Superficially L. schindleri is very similar to L. tropica, but differs in its exciple anatomy. The exciple of both species contains both large and small crystals, but only the small crystals are soluble in K. In L. schindleri the large crystals are not seen initially, being obscured by large amounts of small crystals; the large crystals only become visible once the small ones have been dissolved with K (melacarpella-type). This contrasts with the exciple of L. tropica, which has abundant large crystals that are readily observed, only rarely interspersed, but not obscured, by a few smaller crystals (pulicaris-type).
The two species can further be distinguished by their epihymenia. In L. schindleri small crystals are present; they dissolve in K. Lecanora tropica lacks epihymenial crystals. Both species have the same reddish brown pigment, which persists but fades in K to a dull brown and in HCl turns faint reddish brown again. According to Guderley (1999) this pigment does not dissolve. Following the protocol outlined in Meyer & Printzen (2000) the pigment is nevertheless eventually washed out, especially if 20% KOH and 10% HCl are successively applied. The two species are apparently also distinguished by their spores, though these differences are less obvious; spores are generally smaller and more broadly ellipsoid in L. schindleri compared to those of L. tropica.