Lecanora austrosorediosa Lumbsch (1999: 10) 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 : 7-9

Lecanora austrosorediosa Lumbsch (1999: 10) MycoBank no. 458214

Replacement name for: Biatora sorediosa Rambold (1989 . 75) MycoBank no. 125868

Type:— AUSTRALIA. NORTHERN TERRITORY: Robin Falls, 13 km SSE of Adelaide River , 13°21’S. 131°08’E, 80 m alt., sandstone boulders beside creek, in monsoon forest, 24-Mar-1986, Rambold, G. 5155 (M– holotype!, NT – isotype) .

( Fig. 2A–G )

Thallus saxicolous, thin to strongly thickened, rimose to rimose-areolate, fissures with undulating to very weakly crenate edges, closely adjoining but not interlocked; surface pale bluish gray to pale greenish grey to ivory or grayish white, smooth and epruinose to ±roughened with a coarse, whitish pruina, with pustulate soralia producing white, coarsely granular soredia, without a blackish or bluish hue (see notes below); thalline margin confluent with other, compatible thalli or distinctly delimited by a compact, blackened line, or, where growing unhindered, radiating into a fimbriate, white prothallus. Apothecia sparse to numerous, circular to barely undulate, dispersed to loosely aggregated, rarely closely grouped and deformed (‘gall’-like), 0.1–0.8(–1.0) mm in diam., adnate to soon sessile, biatorine, initially pallid, waxy, pale creamy beige, but becoming partially discolored with age, ±blackened (as if covered in soot), occasionally even young apothecia distinctly blackened and then of lecideine appearance, mostly epruinose, rarely the margin whitish pruinose, disc concolorous to slightly darker in color, pallid, pale creamy beige to blackened, disc and margin C−, K−; hymenium hyaline, not inspersed, epihymenium colorless to brownish, C−, K−, at least in part with diffuse, aeruginose pigment (cinereorufa -green: intensifying in K, HCl+ bluish green, N+ reddish violet), this pigmentation eventually permeating the entire exciple, the overall concentration nevertheless remaining low, the exciple not carbonized (i.e., not becoming brittle from increasing pigmentation), anatomy biatorine, not truly lecideine, inner exciple and hypothecium filled with small, colorless crystals, dissolving in K; hymenium hyaline, not inspersed; thalline exciple absent; asci clavate, Lecanora - type, ascospores 8/ascus, simple, narrowly to broadly ellipsoid, (7.8–)9.9–12.1(–12.7) × (3.9–)4.6–6.0(–6.9) µm (n = 30). Pycnidia immersed, ostiole blackened (brownish and aeruginose pigment), wall hyaline; conidia shortly filiform, ±curved, 13.7–16.7 × ca. 1.0–1.2 µm (n = 5).

Chemistry: Thallus cortex P+ yellow, K+ yellow, KC–, C–, UV– (dull yellow), medulla P+ yellow, K+ yellow, KC–, C–, UV± pale yellow; with atranorin [major], ±2’- O -methylhyperlatolic acid [major, minor or trace], ±zeorin [minor or trace]; the chemistry is apparently a little variable, specimens with 2’- O -methylperlatolic acid [major] and 2’- O -methylsuperlatolic acid [minor or trace] are also known [specimens analyzed with TLC: Bungartz, F. 4398 ( CDS 28483), 4612 ( CDS 28699), 6942 ( CDS 36446), 7885 ( CDS 38394), 9355 ( CDS 46642)].

Ecology and Distribution: Previously considered endemic to Australia, new to Ecuador and the Galapagos, where it is one of the most common saxicolous species, frequently growing together with Caloplaca diplacia (Ach.) Riddle , in dust-rich, ±nitrophytic habitats, on rocks close to the ground, from the coastal zone throughout the dry and transition zones into the humid zone.

Notes: In Galapagos specimens of L. austrosorediosa have regularly been misidentified because of their striking similarity with Caloplaca diplacia . Sectioning apothecia clearly reveals that this species does not belong to the Telochistaceae because it has simple spores formed in typical Lecanora - type asci. Sterile material can also be distinguished since the pustulate soralia of L. austrosorediosa are white, never tinged dirty bluish green as in C. diplacia , their rimose to rimose-areolate thalli are typically pale, grey to greenish grey or almost white whereas the distinctly areolate to subsquamulose thalli of C. diplacia are deep lead- to olive-grey. Of course secondary chemistry also distinguishes the two species: although both contain atranorin, C. diplacia contains isofulgidin, vicanicin and caloploicin whereas L. austrosorediosa instead contains ±2’- O -methylhyperlatolic acid (or closely related secondary metabolites) and zeorin.

Sterile specimens of L. austrosorediosa could also be confused with sorediate forms of L. avium , but this species forms areoles with distinctly serrate margins (similar to those of L. legalloana ). It has bluish grey soralia (similar to those of Caloplaca diplacia , but the thalli of these two species do not resemble one another). Sorediate forms of L. legalloana are unknown. When the three Lecanora species are fertile, they can readily be distinguished: L. avium has black, immersed to sessile, distinctly lecideine apothecia and discs with conspicuous greenish yellow pruina; L. legalloana has deep reddish brown, cryptolecanorine apothecia that do not emerge whereas L. austrosorediosa has apothecia that are distinctly adnate to sessile rather than immersed. They are initially pale cream-colored, with a waxy appearance, only occasionally becoming partially discolored and only rarely completely blackened.

Specimens examined; sorediate material with apothecia. ECUADOR. GALÁPAGOS: San Cristóbal, Pan de Azúcar, inland from Bahía Sardinas at the NW-coast of the island, 0˚43’6’’ S, 89˚21’19’’W, 88 m alt., dry zone, NE-facing slope near the top of the first small hill with low shrubs of Alternanthera filifolia and few Bursera graveolens trees, on rock, 24-Apr-2007, Bungartz, F. 6426 ( CDS 34641). Santiago, 0˚12’0’’ S, 90˚49’30’’W, 15 m alt., dry zone, Bursera forest, on rock, 18-May-1971, Pike, L.H. ID76-4 (L-56478, COLO 260252). Isabela, Volcán Alcedo, along the trail going up the E-slope, at the NW-side of the trail, 0˚24’2’’ S, 91˚2’36’’W, 410 alt., dry zone, basalt boulders and outcrops at the NW-exposed slope of the barranco, Bursera graveolens and Zanthoxylum fagara growing in between, on rock, 09- Mar-2006, Bungartz, F. 4398 ( CDS 28483); basalt rubble field to the SE-side of the trail and the barranco, 0˚24’6’’ S, 91˚2’53’’W, 530 m alt., dry zone, basalt rubble field with scattered vegetation ( Bursera graveolens , Zanthoxylum fagara , Pisonia floribunda , Senna pistaciifolia ), on rock, 10-Mar-2006, Aptroot, A. 64939 ( CDS 31518).

Sorediate material lacking apothecia. ECUADOR. GALÁPAGOS: Floreana, on W-slope of Cerro Alieri, 1˚17’24.10’’ S, 90˚27’8.90’’W, 347 m alt., transition zone, dense forest of Croton scouleri with few Scalesia pedunculata , Citrus sp. and Zanthoxylum fagara , on rock, 12-Jan-2011, Bungartz, F. 9355 ( CDS 46642), F. 9356 ( CDS 46643); Yánez-Ayabaca, A. 1771 ( CDS 48049); trail going to Post Office Bay off the dirt road between highlands and Puerto Velasco Ibarra, 1˚16’57.27’’ S, 90˚26’41.10’’W, 310 m alt., transition zone, open shrubland of Croton scouleri , Zanthoxylum fagara , Macraea laricifolia , Waltheria ovata and lava rocks; Ramalina usnea /anceps forming long curtains hanging from branches, on rock, 14-Jan-2011, Bungartz, F. 9580 ( CDS 46859); at La Lobería, ca. 50 m inland, permanent plot 24, 1˚16’58.89’’ S, 90˚29’26.89’’W, 16 m alt., dry zone, very open Bursera forest with Waltheria ovata , Croton scouleri , few Lantana peduncularis and Mentzelia aspera on lava flow, on rock, 16-Jan-2011, Bungartz, F. 9764 ( CDS 47081). San Cristóbal, Pan de Azúcar, inland from Bahía Sardinas at the NW-coast of the island, 0˚43’6’’ S, 89˚21’19’’W, 88 m alt., dry zone, NE-facing slope near the top of the first small hill with low shrubs of Alternanthera filifolia and few Bursera graveolens trees, on rock, 24-Apr-2007, Bungartz, F. 6425 ( CDS 34640); Cerro Mundo, at the base of the rock cliffs on the S side close to the summit, 0˚53’32.20’’ S, 89˚34’40.5’’W, 243 m alt., transition zone, with Bursera graveolens , Croton scouleri , Piscidia carthagenensis , Zanthoxylum fagara and a few Scalesia pedunculata , slope 45° ESE, basalt rocks on the cliff (microexposition SE), on rock, 25-Aug-2008, Truong, C. 1513 ( CDS 39824). Santiago, along the trail from the caseta in La Central to La Bomba (at the coast), cerro ca. 1 km NE of the caseta and on the W-side of the trail, 0˚14’10’’ S, 90˚44’41’’W, 664 m alt., transition zone, vertical, SEexposed cliff face with ferns ( Blechnum polypodioides and Pityrogramma calomelanos var. calomelanos ) growing in crevices, on rock, 25-Mar-2006, Bungartz, F. 4851 ( CDS 29047); along the trail from Bucanero to Jaboncillos, ca. 3 km SE of Bucanero, 0˚10’52’’ S, 90˚48’33’’W, 362 m alt., transition zone, open woodland of large Bursera graveolens and smaller Psidium galapageium trees, grassland and basalt boulders in between, on rock, 22-Mar-2006, Bungartz, F. 4626 ( CDS 28713), 4612 ( CDS 28699); Aptroot, A. 65396 ( CDS 31982); ca. 1 km S of Bucanero, N-rim of a side-canyon of the big canyon at the northern foothills of Cerro Cowan, 0˚10’25’’ S, 90˚49’26’’W, 91 m alt., dry zone, Sexposed slope of conglomerated ash of the canyon with Bursera graveolens trees and shrubs of Castela galapageia and Vallesia glabra , on rock, 21-Mar-2006, Bungartz, F. 4566 ( CDS 28653); ca. 500 m S of Bucanero, near the canyon at the northeastern foothills of Cerro Cowan, 0˚10’21’’ S, 90˚49’30’’W, 70 m alt., dry zone, open woodland with Castela galapageia , Cordia lutea , Vallesia glabra , Opuntia galapageia , lava, on rock, 21-Mar-2006, Aptroot, A. 65347 ( CDS 31933); summit of Cerro Gavilan, inner N- and NE-exposed crater rim, 0˚12’20’’ S, 90˚47’3’’W, 840 m alt., humid zone, N- and NE-exposed, steep basalt cliffs of crater rim with ferns ( Pityrogramma calomelanos var. calomelanos , Polypodium tridens , Dryopteris palmata , Adiantum concinnum , Blechnum polypodioides ) growing in crevices, lava, on rock, 23-Mar-2006, Aptroot, A. 65748 ( CDS 32340). Isabela, Volcán Alcedo, along the trail going up the E-slope, at the NW-side of the trail, 0˚24’2’’ S, 91˚2’36’’W, 410 m alt., dry zone, basalt boulders and outcrops at the NWexposed slope of the barranco, Bursera graveolens and Zanthoxylum fagara growing in between, on rock, 09-Mar- 2006, Bungartz, F. 4399 ( CDS 28484); Volcán Cerro Azul, lower half of path from the Caseta del Parque to Caleta Iguana at the coast, 0˚58’52.39’’ S, 91˚26’41’’W, 74 m alt., dry zone, shaded forest of huge Manzanillo ( Hippomane mancinella ) trees, some Zanthoxylum fagara scrub, shrubs of Clerodendrum molle and Psidium galapageium , on rock, 09-May-2012, Bungartz, F. 10472 ( CDS 52434); atop basalt cliffs south of Caleta Iguana, 0˚58’51.70’’ S, 91˚26’52’’W, 10 m alt., coastal zone, low woodland of large Manzanillo ( Hippomane mancinella ) trees immediately above the cliffs, on rock, 09-May-2012, Spielmann, A.A. 10743 ( CDS 52146), 10744 ( CDS 52147). Volcán Darwin, southwestern slope, above Tagus Cove, 0˚14’15.4’’ S, 91˚20’40.27’’W, 351 m alt., dry zone, open Bursera graveolens forest with Croton scouleri , Macraea laricifolia and Waltheria ovata , few trees of Acacia rorudiana , on rock, 16-Nov-2007, Bungartz, F. 7885 ( CDS 38394); Volcán Sierra Negra, along dirt road from Puerto Villamil to crater of Sierra Negra, 0˚55’12.4’’ S, 90˚59’38.20’’W, 30 m alt., dry zone, SW-slope of old lava flow with scattered vegetation ( Bursera graveolens , Opuntia echios , and Waltheria ovata ), on rock, 10-Sep-2007, Bungartz, F. 6942 ( CDS 36446).

Figures

FIGURE 2. Species in the L. marginata-group. A–D. Morphological variation of Lecanora austrosorediosa. A–B. Bungartz, F.4398, CDS 28483–holotype. A. Whitish gray, rimose-areolate thallus with smooth surface and fimbriate margin, apothecia adnate to barely sessile, biatorine, pallid, dark-tinged to sordid-blackened, soralia pustulate, with white granular soredia. B. Pale grey, rimose-areolate thallus with smooth surface and fimbriate margin, apothecia adnate to barely sessile, biatorine, pallid, soralia pustulate, with white granular soredia. C–D. Cream-white rimose-areolate thallus with coarse surface, pustulate soralia with white granular soredia, individual thalli delimited by blackened prothallus lines (Bungartz, F. 6426, CDS 34641). C. Part of the specimen with black apothecia appearing ‘lecideine’, their margin covered in grayish white pruina. D. Part of the specimen with pallid biatorine apothecia. E–G. Anatomy of L. austrosorediosa (Bungartz, F. 4398, CDS 28483–holotype). E. Section of dark-tinged, biatorine apothecium, outermost exciple and epihymenium with black pigment [in KOH, crystals dissolved, Differential Interference Contrast (DIC)]. F. Section of pallid, biatorine apothecium (in water, abundantly inspersed by minute crystals, DIC). G. Lecanora-type asci, tholus with wide, apically open, unstained central cone and deeply stained ascus flanks (in Lugol’s iodine, DIC). Scales: A, B, C & D = 5 mm; E & F = 100 µm; G = 15 µm.