Lecanora avium (Zahlbr.) Hertel (1984: 447) MycoBank

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 : 10-11

Lecanora avium (Zahlbr.) Hertel (1984: 447) MycoBank no. 107440

Syn.: Lecidea chilena Zahlbr. (1925: 533) MycoBank no. 390118

Type:— CHILE, JUAN FERNANDEZ: Robinson Crusoe Island (Masatierra), niedriger Felsrücken am Südhang von Tres Puntas, 380 m, 5- Jan-1917, Skottsberg, C. & Skottsberg, I. s.n. [ S – lectotype selected by Hertel (1984), W– isolectotype] .

( Fig. 1C–F )

Thallus saxicolous, thick, contiguous, rimose-areolate, fissures conspicuously interlocked by their crenate edges; surface white, dull, whitish pruinose, ±smooth, very few specimens with laminal, irregularly dispersed, pustulate soralia, sometimes confluent, soredia coarse, with a distinct blackish gray to bluish tinge, pale white inside (sorediate specimens typically lack apothecia); thallus margin delimited by a thin compact, blackened prothallus line, most pronounced where different thalli meet. Apothecia sparse to numerous, circular to barely undulate, 0.2–1.2 mm in diam., initially semi-immersed, then emergent and of “lecanorine” appearance, i.e., with a whitish pruinose, biatorine margin and plane, blackened disc, with age becoming adnate, broadly sessile and distinctly lecideine with a thin, shiny, epruinose, increasingly carbonized margin and a brownish to black, convex disc, densely covered by whitish green to yellowish green pruina (C−, K−); hymenium hyaline, not inspersed, epihymenium with a diffuse aeruginose pigment (cinereorufa -green: intensifying in K, HCl+ bluish green, N+ reddish violet), with sparse clusters of small, dull brown pigment granules that dissolve in K, and with few, large, irregular, hyaline crystals persistent in K; pigmentation and hyaline granules extending to the outer exciple; proper exciple initially weakly to moderately carbonized, pigmentation intensifying with age; thalline exciple absent; hypothecium hyaline; asci clavate, Lecanora - type, ascospores 8/ascus, simple, ellipsoid to broadly ellipsoid, (7.8–)8.9–10.1(–10.3) × (3.9–)4.3–5.5(–6.4) µm (n = 19). Pycnidia immersed, ostiole blackened with brownish and aeruginose pigments (probably the same as in the epihymenium), wall hyaline; conidia shortly filiform, curved, 13.7–17.6 × ca. 1.0–1.5 µm (n = 6).

Chemistry: Thallus cortex and apothecial pruina P+ yellow, K+ yellow, KC−, C−, UV− (dull yellow); with atranorin [major], zeorin [major], leucotylin [minor], unknown terpenes [minor]; [specimens analyzed with TLC: Bungartz, F. 6411 ( CDS 34626), 7280 ( CDS 37764); Ertz, D. 11690 ( CDS 37016)].

Ecology and distribution: Originally described from Juan Fernández Islands ( Chile), also reported from coastal Chile; new to Galapagos, where it is found from the dry to the transition zone, growing on rock in ±exposed habitats.

Notes: Thalli of L. avium are superficially similar to L. austrosorediosa , in particular sorediate specimens without apothecia could easily be confused with this species or even with Caloplaca diplacia , one of the most common saxicolous lichens in the Galapagos. Differences between these three species are discussed under L. austrosorediosa .

The rimose-areolate thallus surface of L. avium , where the fissures have a somewhat crenate to ±serrate margin, is also quite similar in appearance to that of L. legalloana and L. subimmersa . Lecanora avium , however, has distinctly adnate to sessile, lecideine apothecia whereas the apothecia of L. legalloana and L. subimmersa are cryptolecanorine, remaining completely immersed within areoles.

Specimens examined; material with apothecia, lacking soredia. ECUADOR. GALÁPAGOS: Floreana, trail going to Post Office Bay off the dirt road between highlands and Puerto Velasco Ibarra, cliff at NE-side of trail (Mirador), 1˚17’4.298’’ S, 90˚26’36.60’’W, 365 m alt., transition zone, ca. 10 m high lava cliff within dense scrub of Clerodendrum molle , Croton scouleri and Macraea laricifolia , one single Acacia rorudiana on top of cliff, on rock, 25-Jan-2011, Bungartz, F. 10228 ( CDS 47647); just S of Black Beach, dry zone, rocky point, lava, on rock, 26-Apr-1976, Weber, W.A. s.n. (L-63013, COLO 291538). San Cristóbal, rim of crater to the NW of Media Luna, inland from the NWcoast, 0˚43’51’’ S, 89˚18’55’’W, 149 m alt., transition zone, lower transition zone; basalt cliffs of inner and outer crater rim with scarce vegetation, on rock, 22-Apr-2007, Bungartz, F. 6312 ( CDS 34524); near Rosa Blanca, inland from the SE-coast of the island, 0˚49’9’’ S, 89˚21’48’’W, 12 m alt., dry zone, open Bursera graveolens woodland with Mentzelia aspera and Scalesia incensa shrubs on lava flow, on rock, 23-Apr-2007, Bungartz, F. 6411 ( CDS 34626). Santa Cruz, vicinity of Academy Bay, 15-Feb-1964, Weber, W.A. s.n. (L-40834, COLO 193556); near seismic station, dry zone, talus of barranca, on rock, 15-Feb-1964, Weber, W.A. s.n. (L-40868, COLO 190333).

Sorediate material lacking apothecia. ECUADOR. GALÁPAGOS: Santa Fé, top of steep lava cliff above the sea, 0˚47’59.5’’ S, 90˚2’39.20’’W, 16 m alt., coastal zone, scarce vegetation of Croton scouleri , Opuntia echios var. barringtonensis and few Scalesia helleri shrubs, on rock, 25-Oct-2007, Bungartz, F. 7280 ( CDS 37764), Ertz, D. 11690 ( CDS 37016).

Specimens of Lecanora subcoarctata studied for comparison. NEW ZEALAND. NORTH ISLAND: Auckland. Kawaka Bay, east of Auckland, Papanui Point, 36°56’S, 175°13’E, on coastal rocks, immediately above sea level, growing in a high variety of expositions and inclinations, on a hard and brittle siliceous rock type, 12-Jan-1985, Hertel, H. 29135, Mayrhofer, H. & Samuels, G.J. (H. Hertel: Lecideaceae Exsiccatae Nr. 146; COLO 409407, L-78791); same locality, 08-Jan-1985, Mayrhofer, H. s.n. & Samuels, G.J. ( Plantae Graecensis , Institute für Botanik Graz, Lich. 405; COLO 375193, L-84332).

Figures

FIGURE 1. Species in the L. marginata-group. A–B. Lecanora austro-oceanica (Weber 151, L-41000, COLO 190133). A. Thallus areolate with coarse surface, apothecia adnate with coarse grayish pruina. B. Apothecial section [in water, Differential Interference Contrast (DIC)]: outer exciple aeruginose, epihymenium dull brown. C–F. Lecanora avium. C–E. Morphological variation. C. Thallus areolate, delimited by a black prothallus, apothecia adnate, lecideine, disc with greenish yellow pruina (Bungartz, F. 10228, CDS 47647). D. Thallus, areolate, with erumpent pustulate granular soralia tinged dark bluish gray (Bungartz, F. 7280, CDS 37764). E. Thallus areoles with distinctly crenate margin, apothecia adnate, lecideine, disc with greenish yellow pruina (Bungartz, F. 6411, CDS 34626).F.Apothecial section [in water, DIC]: outer exciple aeruginose, epihymenium dull brown (Bungartz, F. 6411, CDS 34626). Scales:A, C, D & E = 5 mm; B & F = 100 µm.