Lecanora strobilina (Sprengel) Kieffer (1895: 74) 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 : 68-69

Lecanora strobilina (Sprengel) Kieffer (1895: 74) MycoBank no. 389285

Basionym: Parmelia strobilina Sprengel (1827: 300) MycoBank no. 398313

Type:— FRANCE. MEDITERRANEAN REGION, exact locality unknown, original label data: “ Gallia merid [ionalis], Pin[us] marit[ima] ”, without date,? Dufour, M. 240 (H-Ach 1141a– holotype) .

non Lecanora strobilina Ach. nom illegit. (1814: 171) MycoBank no. 616529

Taxonomic note: According to Laundon (1967, p. 147) the combination published by Kieffer (1895), based on Sprengel’s basionym Parmelia strobilina must be considered legitimate, and not the name that Acharius (1814) introduced, but himself at the time did not accept. Acharius (1814) listed the name L. strobilina Ach. in his Omissa & Emendanda. According to Laundon (1967) the name must be considered illegitimate, because, while introducing that name, Acharius (1814, p. 341) clearly considered the taxon to be included within Lecanora symmicta : “... Lecanora strobilina & var. betulina . Deleantur, utpote tantum varietatem Lecanora symmictae constituentes. ...” (Shenzhen Code Art 36.1).

( Fig. 18A–E )

Thallus corticolous or lignicolous, thin to moderately thickened, often endosubstratal in part, granular-verrucose, granules ±coalescent, forming a rimose-areolate crust; surface strongly yellowish green or greenish to grayish yellow, matt (in the herbarium developing a fine cover of whitish crystalline needles), lacking soredia; prothallus a blackish line where different thalli meet. Apothecia sparse to numerous, circular or ±irregular, often densely crowded, 0.3–0.7 (–0.9) mm in diam., adnate to sessile, with a distinct lecanorine, ±prominent thalline margin, usually persistent, but with a tendency to be folded back and thus often becoming excluded at least in part, concolorous with or slightly paler than the thallus, coarsely pruinose; disc soon convex, deep yellowish beige to orange, with a greenish to pinkish hue, but not blackened, matt, epruinose or rarely with very fine, inconspicuous pruina; hymenium hyaline, or rarely with a pale yellow tinge, not inspersed; epihymenium with small orange brown granules, soluble in K, lacking distinct crystals, fuscous brown (elachista -brown: dissolving in K, HCl± dull greenish, N−); proper exciple thin, indistinct; thalline exciple without a true cortex, of irregularly entangled, short-celled hyphae, densely filled with small brownish granules that are insoluble in K; subhymenium hyaline to pale yellow, hypothecium hyaline; ascospores 8/ascus, colorless, simple, ellipsoid, (8.5–)10.6–12.4(–16.5) × (3.0–)3.3–3.8(–4.5) µm (n = 30). Pycnidia not seen.

Chemistry: Thallus cortex including apothecial margin P−, C−, KC± yellowish brown, K± yellowish brown, UV−(dull); containing usnic acid [major], decarboxysquamatic acid [minor], squamatic acid [minor], zeorin [minor]; [specimens analyzed with TLC: Aptroot, A. 65420 ( CDS 32006); Bungartz, F. 7494 ( CDS 37981), 7728 ( CDS 38232), 8198 ( CDS 40844), 8201 ( CDS 40847); Nugra, F. 124 ( CDS 32778)].

Ecology and distribution: A temperate to Mediterranean species (North America, North Africa, SW Europe; see Ryan et al. 2004), new to South America, Ecuador and the Galapagos; moderately common in dry and transition zone vegetation, in open woodland and scrub, in sunny, exposed habitats, on bark, wood or dried plant debris.

Notes: Lecanora strobilina always lacks xanthones so that the conspicuous yellowish green thalli do not fluoresce under UV and are always C−/KC−. On prolonged storage herbarium specimens often develop a fine, whitish 'fur' of needle-shaped crystals due to high concentrations of terpenes (previously observed by Printzen 2001). Superficially this species resembles L. confusoides which often occurs in similar habitats. However, all specimens of L. confusoides contain xanthones and react C+/KC+ orange; this species typically has a duller thallus and herbarium specimens never develop a coating of terpene crystals. Further, the apothecia of L. confusoides are regularly discolored with an olivaceous to grayish black tinge. Lecanora strobilina is readily characterized by its unusual secondary chemistry: decarboxysquamatic acid can be detected by TLC, appearing as a pale beige to pale green spot, fluorescing brightly blue in long wave UV (λ 365), often with a long bluish tail after H 2 SO 4 treatment and heating. In solvent C the spot develops just below zeorin.

Specimens examined. ECUADOR. GALÁPAGOS: Santiago, en el parte sureste de la isla, 0˚16’38.39’’ S, 90˚37’23.80’’W, 163 m alt., zona seca, bosque de Bursera graveolens y pocos árboles de Scalesia atractyloides , sobre lava joven, Bursera graveolens muerto, sobre corteza, 20-Jul-2006, Nugra, F. 124 ( CDS 32778); ca. 5 km inland from the E-coast, ± at the same latitude as Bahía Sullivan, 0˚16’52’’ S, 90˚37’17’’W, 175 m alt., dry zone, rubble of older lava with very scarce vegetation of few Bursera graveolens trees, Macraea laricifolia , and Mentzelia aspera , on dead wood of standing tree ( Bursera graveolens ), 16-Jul-2006, Bungartz, F. 5045 ( CDS 29258); ca. 1km 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, S-exposed slope of conglomerated ash of the canyon with Bursera graveolens trees and shrubs of Castela galapageia and Vallesia glabra , on wood, 21-Mar-2006, Bungartz, F. 4572 ( CDS 28659); along the trail from Bucanero to Jaboncillos, ca. 5 km SE of Bucanero, 0˚11’19’’ S, 90˚47’48’’W, 562 m alt., transition zone, open woodland of large Bursera graveolens and smaller Psidium galapageium trees with Blainvillea dichotoma , Mentzelia aspera and Senna obtusifolia in between, Psidium , on bark, 22-Mar-2006, Aptroot, A. 65420 ( CDS 32006). Isabela, Volcán Alcedo, in the crater near fumaroles, 0˚27’1’’ S, 91˚7’19’’W, 780 m alt., transition zone, sulphur-influenced scrub on uneven lava, on wood, 07-Mar-2006, Aptroot, A. 64809 ( CDS 31384). Volcán Darwin, southwestern slope, above Tagus Cove, 0˚13’59’’ S, 91˚20’8’’W, 597 m alt., dry zone, open Bursera graveolens forest with Croton scouleri and Macraea laricifolia shrubs, few Chiococca alba and Scalesia microcephala , among lava boulders and outcrops, on twig of Bursera graveolens , 16-Nov-2007, Bungartz, F. 7859 ( CDS 38368), 7816 ( CDS 38325); 0˚13’43.27’’ S, 91˚19’47.27’’W, 724 m alt., transition zone, SW-exposed lava flow of weathered AA-lava with scarce vegetation ( Macraea laricifolia , Dodonaea viscosa , Croton scouleri , Cordia revoluta and Jasminocereus thouarsii ), on dead twigs of Dodonaea viscosa , 12-Nov-2007, Bungartz, F. 7494 ( CDS 37981), 7466 ( CDS 37953); 0˚13’27’’ S, 91˚19’19.5’’W, 874 m alt., transition zone, top of lava flow in open scrubland of Croton scouleri and Dodonaea viscosa with Cordia revoluta and some Opuntia insularis , on Croton scouleri stem, 15-Nov-2007, Bungartz, F. 7728 ( CDS 38232); 0˚13’25.60’’ S, 91˚19’13.80’’W, 900 m alt., transition zone, top of lava flow of weathered AA-lava with scarce vegetation ( Jasminocereus thouarsii , Dodonaea viscosa , Chiococca alba , Macraea laricifolia ), on dead twig of Dodonaea viscosa , 15-Nov-2007, Bungartz, F. 7770 ( CDS 38278). Volcán Sierra Negra, El Mango, on the E-side of the dirt road, 0˚53’1.7’’ S, 91˚0’50.77’’W, 162 m alt., transition zone, lower transition zone; basalt lava outcrop with scattered vegetation ( Polypodium sp. , Pityrogramma calomelanos , Darwiniothamnus tenuifolia ), N-exposed slope, on dead stems and blade of Polypodium fronds, 15-Aug-2008, Bungartz, F. 8198 ( CDS 40844), 8201 ( CDS 40847); 0˚53’1.399’’ S, 91˚0’48.39’’W, 161 m alt., transition zone, rocky area (open) with shrubs of Psidium guajava , ferns and Stereocaulon covering the ground, at the top of a rocky outcrop (exposed), On Polypodium branches and leaves on the ground, 15-Aug-2008, Truong, C. 1233 ( CDS 39544).

Non-Galapagos specimen examined for comparison: MEXICO. BAJA CALIFORNIA SUR. 21 km SW of Hwy 1, along road to Puerto Cancun at turnoff to Cayuco , 24˚35’W, 111˚45’W, 50 m alt., on wood, 19-Feb-1993, Nash II , T. H. 33937 ( ASU) ( TLC Elix: usnic acid [major], decarboxysquamatic acid [minor], squamatic acid [minor], zeorin [minor]) .

Figures

FIGURE 18. Species in the L. varia-group.A–E. Lecanora strobilina. A–B. Thallus variation.A. thick rimose-areolate,pale yellow thallus with adnate apothecia, farinose soredia developing irregularly from the thallus surface and along the apothecial margin, discs epruinose, golden yellow (Nugra, F. 124, CDS 32778). B. scant rimose thallus on a black hypothallus, farinose soredia forming irregular from the surface and apothecial margin, discs epruinose, golden yellow (Bungartz, F. 7859, CDS 38368). C–E. Apothecial section (Nugra, F. 124, CDS 32778). C. Exciple abundantly filled with minute crystals and yellowish brown pigment, pigment and crystals extending across epihymenium, hypothecium hyaline (in water, DIC). D. After treatment with 10% KOH, crystals and pigments dissolved, trebouxioid photobionts more easily distinguished (in KOH, DIC). E. Characteristically small, narrowly oblong ascospores (in KOH, DIC). F. Leproid thallus of Lecanora terpenoidea, sorediate granules embedded among cottony thallus hyphae, with prolonged herbarium storage forming abundant terpenoid crystals that give the thallus a conspicuous ‘fluffy’ appearance (Aptroot, A. 65410, CDS 31996–holotype). Scales: A, B & F= 5 mm; C & D =100 µm; E = 10µm.