Lecanora subfusca

Bungartz, Frank, Elix, John A. & Printzen, Christian, 2020, Lecanoroid lichens in the Galapagos Islands: the genera Lecanora, Protoparmeliopsis, and Vainionora (Lecanoraceae, Lecanoromycetes), Phytotaxa 431 (1), pp. 1-85 : 36

Lecanora subfusca -group ( Lecanora s.str., Figs 10–15 )

The L. subfusca -group, containing the generic type L. subfusca , can be considered the “core group” of Lecanora and is characterized by lecanorine, usually sessile apothecia with pale to deep reddish brown, rarely ± blackened, epruinose discs. The thalline exciple contains either characteristic large crystals that are insoluble in K and/or small crystals usually soluble in K. The thallus is granular to rimose or areolate with a white or pale to dark grey, rarely greenish or ± yellowish green ( L. queenslandica -group) surface. All species of the group have filiform conidia. Ten of the twelve species occurring on Galapagos produce atranorin as major substance and the other two produce usnic acid.

Figures

FIGURE 10. Species in the L. subfusca-group; superficially similar species with pale apothecial disc and pulicaris-type exciple (large crystals only). A–B. Lecanora achroa (Nugra, F. 111, CDS 32765). A. Thick rimose-areolate, white thallus with lecanorine apothecia with pale brown discs, growing on smooth bark of Bursera. B. Apothecial section with chlarotera-type epihymenium and pulicaris-type exciple. C–D. Lecanora leprosa. C. White, dispersed thallus granules on whitish prothallus with lecanorine apothecia with pale yellowish green discs, on smooth bark of Bursera (Bungartz, F. 6319, CDS 34534). D. Apothecial section with chlarotera-type epihymenium and pulicaris-type exciple (Bungartz, F. 6039, CDS 33718). E–F. Lecanora sulfurescens. E. White thallus with lecanorine apothecia with pale brown discs, growing on rock (Bungartz, F. 4054, CDS 27984). F. Apothecial section with pulicaris-type epihymenium and pulicaris-type exciple (Bungartz, F. 6562, CDS 34780). Scales: A, C, & E = 5 mm; B, D & F = 100 µm.

FIGURE 11. Species in the L. subfusca-group; superficially similar species with brown apothecial disc and pulicaris-type exciple (large crystals only). A–C. Ecological thallus variation of Lecanora sulfurescens. A. Scantly developed, thin thallus with net-like areoles, apothecia with pale greenish yellow disc; developed below shaded overhang on coarse lava (Bungartz, F. 4386, CDS 28471). B. Thallus of minute, scattered, isolated, granular areoles, apothecial disc chestnut brown; growing on strongly weathered rock with ±disintegrating mineral surface (Bungartz, F.6416, CDS 34631). C. Smooth, contiguous areolate thallus delimited by blackened prothallus line, apothecial disc chestnut brown; growing on smooth basalt surface (Bungartz, F. 4822, CDS 28988). D.–F. Lecanora galactiniza. D. Exuberant, thick areolate thallus with marginal areoles becoming subsquamulose, apothecial disc chestnut brown; growing at a nutrient-rich site (Bungartz, F.4706, CDS 28804). E. Thallus of discrete, dispersed squamules, apothecial disc dark brown; growing on coarse, irregular lava (Bungartz, F. 5207, CDS 29420). F. Section of apothecium with pulicaris-type exciple (with large crystals only) and pulicaris-type epihymenium (deep brown pigment not dissolving, but minute crystals dissolving in KOH; in KOH, DIC). Scales: A–E = 5 mm; F = 100 µm.

FIGURE 12. Species in the L. subfusca-group; superficially similar species with deep brown apothecial disc and pulicaris-type exciple (large crystals only). A–B. Lecanora schindleri (Weber, W. A. s.n., L-40337, COLO 188861). A. Thallus continuous to barely rimose with fimbriate whitish prothallus, apothecia adnate to sessile, margin entire, disc deep reddish brown to almost blackish brown, epruinose or with very faint, whitish pruina. B. Apothecial section (in water, DIC), exciple with abundant minute, soluble crystals obscuring few large, insoluble ones (melacarpella-type), epihymenium with reddish brown, insoluble pigment and minute soluble crystals (pulicaris-type). C– D. Lecanora tropica. C. Thallus rimose-areolate, slightly verrucose, delimited by a darkened prothallus line, apothecia adnate to sessile, margin entire to ±crenulate, disc deep reddish brown, epruinose (Bungartz, F. 8425, CDS 41071). D. Apothecial section (in water, DIC): exciple with conspicuous, large, insoluble crystals and few minute, soluble ones (pulicaris-type), epihymenium with insoluble brown pigment, lacking crystals (glabrata-type) (Dawson, E.Y. s.n., L-40089, COLO 188062). E–F. L. subimmergens (Bungartz, F. 7600, CDS 38096). E. Thallus areolate, apothecia adnate to sessile, margin entire, slightly undulate, disc dark reddish to blackish brown, epruinose. F. Apothecial section (in water, DIC): exciple with conspicuous, large, insoluble crystals and few minute, soluble ones (pulicaris-type), epihymenium with insoluble brown pigment, lacking crystals (glabrata-type). Scales: A, C & E = 5 mm; B, D & F = 100 µm.

FIGURE 13. Species in the L. subfusca-group; superficially similar species with pale to dark brown apothecial disc and melacarpella- or allophana-type exciple (coarse and fine or fine crystals only). A–B. Lecanora darwiniana (Bungartz, F. 4859, CDS 29055–holotype). A. Thallus rimose, with abundant, coarsely granular soredia all across its surface and along the apothecial margin, apothecial disc deep brown, epruinose. B. Apothecial section: exciple with both coarse and fine crystals (melacarpella-type), epihymenium lacking crystals, brownish pigment insoluble in K (glabrata-type), exciple breaking apart into granular soredia (in water, DIC). C–D. Lecanora cactacea (Bungartz, F. 8178, CDS 40824–holotype). C. Thallus areolate verrucose, growing on the flaky surface of cactus pads, apothecia large, distinctly sessile, margin soon conspicuously fissured, disc pale to deep brown, with age occasionally blackened. D. Apothecial section (in water, DIC): exciple evenly yellow brown throughout, filled with abundant, minute crystals that completely dissolve in KOH (allophana- type), epihymenium yellowish brown, not dissolving in KOH, lacking crystals (glabrata-type). E–F. Lecanora subcrenulata (Bungartz, F. 7617, CDS 38113). E. Thallus saxicolous, areolate, with large, distinctly sessile apothecia, margin moderately to strongly undulate with age, disc pale orange-brown, epruinose. G. Apothecial section (in water, DIC): exciple with both coarse and fine crystals (melacarpella- type), epihymenium with minute crystals and brown pigment (chlarotera-type). Scales: A, C, & E = 5 mm; B, D & F = 100 µm.

FIGURE 14. Sorediate species in the L. subfusca-group; epihymenium at least in part aeruginose. A–C. Lecanora floridula A–B. Morphological variation. A. Thallus pale greenish gray, rimose-areolate, with pustulate yellow green soralia and broadened apothecia with deep brown disc (Bungartz, A. 8616, CDS 41262). B. Thallus rimose, yellow green, with pustulate yellow green soralia, apothecia indistinct, disc barely expanded, dark brown (Bungartz, F. 6474, CDS 34691). C. Apothecial section (in water, DIC): exciple with large crystals (pulicaris-type), epihymenium mostly brown, with few crystals (chlarotera-type), but in parts also aeruginose (Aptroot, A. 64915, CDS 31494).D–G. Lecanora malagae (Bungartz, F.10352, CDS 52326–holotype).D. General thallus aspect,composed of inflated,closely aggregated, pale gray areoles with pustulate pale yellowish green soralia, apothecia with a thick margin, disc bluish blackened, faintly pruinose. E. Close-up of the thallus. F. Lecanora-type ascus, tholus with wide, apically open, unstained central cone and deeply stained ascus flanks (in Lugol’s, DIC). G. Apothecial section (in water, DIC): exciple with minute crystals only (allophana-type), epihymenium aeruginose, lacking crystals (gangaleoides-type). Scales: A, D, B & E = 5 mm; F = 10 µm; C & G = 100 µm.

FIGURE 15. Other species in the L. subfusca-group. A–C. Lecanora kalbii (Bungartz, F. 6432, CDS 34647–holotype). A. Coarsely granular to bullate areolate, white thallus with crenate lecanorine apothecia and blackened epruinose disc. B. Apothecial section (in water, DIC): exciple with large crystals only, not dissolving in K (pulicaris-type), epihymenium brownish black, lacking crystals; subhymenium distinctly developed, pale yellowish brown (cf. glabrata-type). C. Filiform conidia. D–E. Lecanora ombligulata (Bungartz, F. 7008, CDS 36515–holotype). D. ±Cerebriform, minutely peltate-umbilicate thallus with blackened apothecia. E. Apothecial section (in water, DIC): exciple filled with abundant, minute crystals (allophana-type), epihymenium bluish-black (gangaleoides-type). Scales: A & D = 5 mm; B & E = 100 µm; C =5 µm.