Lecanora malagae Bungartz & Elix, 2020

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 : 52-53

Lecanora malagae Bungartz & Elix sp. nov. MycoBank no. 833374

Diagnosis. Similar to Lecanora floridula , but growing on rock and having a distinctly aeruginose epihymenium which lacks crystals (gangaleoides - type) and an exciple with only minute crystals (allophana - type).

Type:— ECUADOR. GALÁPAGOS: Isabela, Volcán Cerro Azul, lower slopes of small, vegetated peak along the western crater rim, 0˚56’20.4’’ S , 91˚25’24’’W, 1630 m, high altitude dry zone, large basalt rock outcrop (basalt cliff) below the highest point of the volcano, surrounded by black volcanic ash fields, few grasses and sedges ( Cyperus anderssonii ), Alternathera, and some ferns, on north facing, sunny, wind- and rain exposed rock, 05-May-2012, Bungartz, F. 10352 ( CDS 52326 – holotype) .

( Fig. 14D–G )

Thallus saxicolous, moderately thickened, areolate, areoles swollen, bullate, i.e., ±aggregated in convex clusters and deformed by mutual pressure; surface pale yellowish green to yellowish gray, smooth, matt, epruinose, sorediate; soralia pustulate, convex, initially distinctly delimited, but in older thalli becoming coalescent, then at least in parts covering and thus obscuring the thallus, soredia yellowish to greenish white, mealy to ±granular, generally brighter in color than the thallus; prothallus absent. Apothecia sparse to ±numerous, circular, 0.1–0.8 mm in diam., sessile, distinctly lecanorine, margin persistent, undulate to crenulate, smooth, epruinose, concolorous with the thallus, rarely disintegrating into soredia, disc ±plane, deep olive brown or blackened, typically obscured by a farinose, whitish grey pruina; hymenium hyaline, not inspersed, epihymenium with a weak, diffuse orange-brown pigment (cf. elachista - brown: dissolving in K, HCl± dull greenish brown, N−; adding K after N causes the formation of ca. 1 µm big, fuscous brown granules), additionally in parts discolored also by an aeruginose pigment (cinereorufa -green: intensifying in K, HCl+ bluish green, N+ reddish violet), crystals absent, brown pigment dissolving, aeruginose pigment persistent (± gangaleoides - type); proper exciple thin, indistinct, with few crystals; thalline exciple thick, ecorticate to indistinctly corticate, pale blackish wine-red along the outside, only with minute crystals, soluble in K (allophana - type); subhymenium and hypothecium hyaline; ascospores 8/ascus, simple, ellipsoid, (7.8–)9.5–12.5(–13.7) × (3.9–)4.8– 6.5(–6.9) µm (n = 30). Pycnidia not seen.

Chemistry: Thallus cortex and apothecial margin P+ yellow, K+ yellow, C−, KC−, UV−; with atranorin [major], usnic acid [major], zeorin [major], often also with SV-1 [minor; derived from photobiont, of no taxonomic value]; [specimens examined with TLC: Aptroot, A. 65247 ( CDS 31833), Bungartz, F. 4137 ( CDS 28168), 4142 ( CDS 28168), 4175 ( CDS 28206), 9431 ( CDS 46718)]. Two sterile specimens contain arthothelin and asemone, they react C+ yellowish orange, UV+ bright yellow [Aptroot, A. 65295 ( CDS 31881), Bungartz, F. 4130 ( CDS 28161)].

Etymology: Named in honor of Jeffreys Malaga, a Galapagos National Park Ranger and a native of San Cristóbal Island. Jeffreys became a good friend while guiding us in the field. We much enjoyed his company, his great sense of humor, professionalism and unique curiosity for the natural world of these islands.

Ecology and Distribution: Known only from the Galapagos; fertile specimens have only been collected from rock outcrops in the fog-desert ash fields of the high altitude dry zone of Volcán Cerro Azul; thalli without apothecia have also been found on rock outcrops in the humid zone of Volcán Alcedo, and the upper transition zone of Cerro Asilo de la Paz in Floreana.

Notes: This species is similar to L. floridula , but saxicolous and characterized by an exciple that lacks large crystals and an epihymenium without any crystals. Unlike the flattened, angular, pale green areoles of the European Lecanora soralifera (Suza) Räsänen , areoles of L. malagae are strongly convex, swollen and pale gray in color. In addition to usnic acid and zeorin, specimens of L. malagae always contain atranorin. Some of the sterile specimens may also contain additional xanthones (arthothelin and asemone, material cited below). The sterile specimens closely resemble Trapelia coarctata (Turner) M. Choisy , but individual areoles of L. malagae are typically larger, more convex and react C– (or, if xanthones are present C+ yellowish orange, but not reddish).

Additional pecimens examined; fertile, without xanthones (paratypes). ECUADOR. GALÁPAGOS: Isabela, Volcán Cerro Azul, lower slopes of small, vegetated peak along the western crater rim, 0˚56’20.39’’ S , 91˚25’24’’W, 1630 m alt., high altitude dry zone, large basalt rock outcrop below the highest point of the volcano, surrounded by black volcanic ash fields, few grasses and sedges ( Cyperus anderssonii ), Alternathera, and some ferns, Basalt cliff, sunny, wind/rain exposed, top and slope of rock, outcrop, north facing, on rock, 05-May-2012, Bungartz, F. 10352 ( CDS 52326 ) .

Sterile, without xanthones. ECUADOR. GALÁPAGOS: Volcán Alcedo, Isabela, outer SE-exposed slope, ca. 100 m below the crater rim, 0˚25’36’’ S, 91˚5’12’’W, 1146 m alt., humid zone, disturbed by former grazing of goats, Pteridium arachnoideum and Stachytarpheta cayennensis , scattered low shrubs of Tournefortia rufo-sericea and outcrops of basalt tuff in between, top of E-exposed basalt outcrop; sunny, wind- and rain- exposed, on rock, 06-Mar-2006, Bungartz, F. 4137 ( CDS 28168); Bungartz, F. 4142 (, CDS 28173); Bungartz, F. 4175 ( CDS 28206); on the crater rim near the hut, 0˚26’33’’ S, 91˚5’31’’W, 1100 m alt., humid zone, Pteridium arachnoideum and Stachytarpheta cayennensis , scattered low shrubs of Tournefortia rufo-sericea and outcrops of basalt tuff in between, basalt, on rock, 07-Mar-2006, Aptroot, A. 65247 ( CDS 31833). Isla Floreana, Pampa Larga, S of Cerro Asilo de la Paz, 1˚19’38.70’’ S, 90˚27’11.6’’W, 249 m alt., transition zone, herbaceous vegetation with dominant Phyla strigulosa , occasional grasses and other herbs, few small shrubs of Geoffroea spinosa , top of small basalt rock lying on the ground; sunny, wind- and rain-exposed, on rock, 13-Jan-2011, Bungartz, F. 9431 ( CDS 46718).

Sterile, with xanthones. Volcán Alcedo, Isabela, outer SE-exposed slope, ca. 100 m below the crater rim, 0˚25’36’’ S, 91˚5’12’’W, 1146 m alt., humid zone, disturbed by former grazing of goats, Pteridium arachnoideum and Stachytarpheta cayennensis , scattered low shrubs of Tournefortia rufo-sericea and outcrops of basalt tuff in between, top of E-exposed basalt outcrop; sunny, wind- and rain- exposed, on rock, 06-Mar-2006, Bungartz, F. 4130 ( CDS 28161); on the crater rim near the hut, 0˚26’33’’ S, 91˚5’31’’W, 1100 m alt., humid zone, Pteridium arachnoideum and Stachytarpheta cayennensis , scattered low shrubs of Tournefortia rufo-sericea and outcrops of basalt tuff in between, basalt, on rock, 07-Mar-2006, Aptroot, A. 65295 ( CDS 31881).

Figures

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.