Vainionora nugrae 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 : 75

Vainionora nugrae Bungartz & Elix sp. nov. MycoBank no. 833381

Diagnosis. Thallus corticolous, verruculose areolate to bullate areolate, faint yellowish green; apothecia sessile, crenate, with olivaceous to blackened, faintly pruinose disc, subhymenium hyaline, hypothecium deep yellowish brown; containing atranorin, thiophanic acid and arthothelin.

Type:— ECUADOR. GALÁPAGOS: Santa Cruz, cerca la vía sector Los Gemelos, 0˚38’2.1’’ S, 90˚23’37.9’’W, 661 m alt., zona de transición, bosque de Scalesia pedunculata , bosque secundario, perturbado y restaurado, sobre corteza de Psidium galapageium , altura al pecho, 04-Jan-2007, Nugra, F. 279 ( CDS 33195– holotype).

( Fig. 20C–D )

Thallus corticolous, moderately thickened, verrucose-areolate to bullate-areolate; surface faint yellowish green, smooth, matt, epruinose, lacking soredia; prothallus absent or present as a faint whitish layer extending between the granular areoles, rarely delimiting the thallus outline as a black line. Apothecia numerous, often densely aggregated, circular, 0.4–0.8(-1.1) mm in diam., adnate to sessile, often crowded, distinctly lecanorine, margin smooth to coarsely crenulate, epruinose, concolorous with the thallus, disc plane to slightly convex, deep olivaceous to ±blackened, with a faint, farinose, yellowish green pruina; hymenium hyaline, not inspersed, epihymenium with fine, granular crystals, olive brown, infused by a mixture of fuscous brown (elachista -brown: dissolving in K, HCl± dull greenish, N−) and aeruginose pigments (cinereorufa -green: intensifying in K, HCl+ bluish green, N+ reddish violet), crystals and pigments soluble in K; proper exciple thin, indistinct, lacking crystals; thalline exciple thick, ±corticate, with large crystals only, insoluble in K; subhymenium hyaline, hypothecium deep red-brown (leptocline -brown: K+ orange brown, HCl+ intensely reddish brown, N−); ascospores 8/ascus, simple, ellipsoid, (7.8–)10.3–13.9(–16.7) × (4.9–)5.1–7.4 (–9.8) µm (n = 25). Pycnidia not seen.

Chemistry: Thallus cortex P± yellowish, K+ yellow, KC+ orange, C+ orange, UV+ pale orange; with atranorin [minor], thiophanic acid [major] and arthothelin [minor]; [specimen analyzed with TLC: Nugra, F. 279 ( CDS 33195 – holotype)] .

Etymology: Named in honor of Fredy Nugra, who collected the type and only specimen.

Ecology and Distribution: At present known only from the type specimen which was collected in upper transition zone forest, on bark of Psidium galapageium .

Notes: When clarifying the concept of Vainionora Kalb & Elix (2004) emphasized that species of the genus had a well-developed, pigmented subhymenium, but a colorless hypothecium. In their revision of species of Lecanora with dark pigmented hypothecium Lumbsch et al. (1996) did not distinguish two alternatively pigmented layers (subhymenium and hypothecium) immediately below the hymenium. They considered species with a pigmented hypothecium and filiform conidia to belong to Lecanora s.str. ( L. coronulans -group), but species with bacilliform conidia were placed in Vainionora ( Lumbsch et al. 1996, p. 286, table 2).

Vainionora nugrae has a distinctly orange-brown layer of hyphae present below the hymenium, but the hyphae immediately below the hymenium are actually colorless. This layer is structurally different from the layer of asci and paraphyses immediately above, it is clearly not pigmented as the layer immediately below ( Fig18D ). Following a terminology discussed in detail by Bungartz (2002), this thin, unpigmented layer of ascogeneous hyphae immediately below the hymenium corresponds to the subhymenium, whereas the pigmented layer further below should be called the hypothecium. Laterally these pigmented hyphae extend into the proper exciple, whereas the unpigmented hyphae still further below are structurally part of the thalline exciple.

Unfortunately conidia could not be found in V. nugrae , but as the thallus contains both xanthones and atranorin, it is accommodated here in Vainionora .

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.

FIGURE 20. Species of Vainionora. A–B. Thallus variation of Vainionora aemulans. A. Granular-leproid thallus growing on smooth bark of Zanthoxylon (Aptroot, A. 65060, CDS 31642). B. Granular-leproid thallus growing on coarse basalt lava (Aptroot, A. 65170, CDS 31754). C–D. Vainionora nugrae (Nugra, F. 279, CDS 33195–holotype). C. Thallus coarsely granular, pale yellowish green, with crenate lecanorine apothecia with blackened disc covered in a fine yellowish green pruina. D. Apothecial section (in water, DIC): exciple with large crystals only; epihymenium yellowish brown, lacking crystals; subhymenium well developed, distinctly yellowish brown. Scales: A, B & C = 5 mm; D =100 µm.