Lecanora baekdudaeganensis B.G. Lee & J-.S. Hur, 2020

Lee, Beeyoung Gun & Hur, Jae-Seoun, 2020, A new lichenized fungus, Lecanora baekdudaeganensis, from South Korea, with a taxonomic key for Korean Lecanora species, MycoKeys 70, pp. 39-58 : 39

Lecanora baekdudaeganensis B.G. Lee & J-.S. Hur sp. nov. Fig. 4

Diagnosis.

Lecanora baekdudaeganensis differs from L. imshaugii by a darker thallus (bluish, olivish, or pale brownish gray vs. greenish or yellowish gray), brownish disc (vs. reddish brown disc), K-insoluble granules on the surface of epihymenium (vs. absence of granules), shorter hypothecium (15-25 μm vs. 50-75 μm), and the presence of oil droplets in the apothecial section.

Type.

South Korea, North Gyeongsang Province, Bonghwa-gun, Chunyang-myeon, Mt. Munsu, 36°59.41'N, 128°48.24'E, 1,005 m alt., on bark of Quercus mongolica Fisch. ex Ledeb., 29 August 2019, B.G.Lee 2019-000065 (holotype: BDNA-L-0000065!; GenBank MN879847 for ITS and MN879871 for mtSSU); South Korea, North Gyeongsang Province, Bonghwa-gun, Chunyang-myeon, Mt. Munsu, 37°0.31'N, 128°47.39'E, ca 900 m alt., on bark of Quercus dentata Thunb., 26 September 2019, B.G.Lee 2019-000135 (paratype: BDNA-L-0000135); South Korea, North Gyeongsang Province, Bonghwa-gun, Chunyang-myeon, Mt. Munsu, 36°59.82'N, 128°46.81'E, 970 m alt., on bark of Quercus mongolica , 26 August 2019, B.G.Lee 2019-000147 (paratype: BDNA-L-0000147); South Korea, North Gyeongsang Province, Bonghwa-gun, Chunyang-myeon, Mt. Munsu, 36°59.35'N, 128°46.12'E, ca 1,075 m alt., on bark of Quercus mongolica , 26 August 2019, B.G.Lee 2019-000151 (paratype: BDNA-L-0000151).

Description.

Thallus corticolous, crustose, without lobes, continuous or cracked, rimose to areolate or verruculose, usually rounded or irregular, bluish gray in the beginning (margin) and olivish- or pale brownish-gray when mature (center), not pruinose, 30-70 mm diam., 100-170 μm thick; cortex hyaline to pale yellow or pale brown, 5-10 μm thick; medulla 20-75 μm thick; photobiont coccoid, forming a distinct algal layer, 45-80 μm thick, cells globose, 8.5-17 × 8-15 μm. Prothallus absent.

Apothecia abundant, rounded, smaller and scattered around the margin and larger and aggregated in the center, constricted at the base, 0.2-1.6 mm diam. Disc flat to slightly concave, not pruinose, brown to dark brown from the beginning, 270-430 μm thick; margin persistent, prominent, generally entire or slightly flexuous, some a little crenulate when old, concolorous to thallus. Amphithecium well-developed, with numerous small crystals in both algal-containing and cortical parts ( allophana -type) not dissolving in K, 60-100 μm thick laterally, 110-130 μm thick basally; amphithecial cortex distinct, 7-12 μm thick. Parathecium hyaline, indistinct in water, 15-25 μm thick in I. Epihymenium pale yellowish brown to pale brown, with small granules on the surface not dissolving in K, pigment slightly paler in K but not diluted, without oil droplets, 5-15 μm high. Hymenium hyaline, 50-75 μm high. Subhymenium hyaline, 20-40 μm high. Hypothecium hyaline, coarsely prosoplectenchymatous (periclinal) in the lower and marginal parts and prosoplectenchymatous (irregular) in the upper and central parts, 15-25 μm high. Oil droplets present in hypothecium, subhymenium and the base of hymenium. Hypothecial base not extending or a little extending to the substrate and always closed by medulla of amphithecium. Paraphyses septate, anastomosing, 1-2.5 μm wide, simple or sparsely branched at tips but not, or only slightly, swollen, 2.5-4 μm. Asci clavate, 8-spored, 41-51 × 13-20 μm (n = 10). Ascospores simple, often biguttulate in the beginning then having an oval-shaped oil drop by assembly of guttules when mature, narrowly or widely ellipsoid, or eye-shaped, 10-18.5 × 4.5-9.5 μm (mean = 15.2 × 6.5; SD = 1.58 (L), 1.10 (W); n = 128), wall ca 0.5 μm thick when exist. Pycnidia only once detected, pale brown at tip, ovoid, 315 × 330 μm, without conidia as old.

Chemistry.

Thallus K+ yellow, KC+ yellow, C-, Pd-. Hymenium I- in the beginning but turning slowly blue or purple-blue, KI+ blue (reaction mainly starting from tholus then the whole ascus), C-, Pd-. UV-. Atranorin, zeorin and an unidentified minor constituent (Rf classes A3 and C3 in Culberson’s standardized thin layer chromatography method ( Culberson 1972)), UV- before heating, spot color slightly pale yellow-orange after heating, and UV+ pale pink-orange after heating) were detected by TLC.

Distribution and ecology.

The species occurs on the bark of Quercus mongolica and Q. dentata which are the most dominant tree species on the mountain. This species is currently known from four different sites on the mountain.

Etymology.

The species epithet indicates the lichen’s geography, namely the main mountains called Baekdudaegan stretching from north to south in the entire Korean Peninsula.

Notes.

The new species is classified to the Lecanora subfusca group - allophana type, representing the main characteristics of a crustose thallus without lobes containing atranorin as a major constituent, small calcium oxalate crystals in both algal-containing and cortical parts of the amphithecium, and trebouxioid photobionts in the thalline margin, dark brown discs, and colorless ellipsoid simple spores in the range of 10-20 × 6-9 μm ( Brodo 1984; Miyawaki 1988; Lumbsch 1995; Lumbsch et al. 2003). The new species is compared with Lecanora chionocarpa Hue, L. horiza , L. imshaugii , L. japonica Müll. Arg., and L. megalocheila (Hue) H. Miyaw., as those species are in the L. subfusca group with only small crystals in the amphithecium ( allophana or campestris type) which is defined by the main characteristics such as K+ yellow thallus reaction (containing atranorin), small calcium oxalate crystals in algal-containing and/or cortical parts of amphithecium, and ascospores in the size of 10-20 × 6-9 μm ( Hue 1915; Brodo 1984; Miyawaki 1988; Smith et al. 2009). The new species is most similar to L. imshaugii by a continuous, rimose, verruculose or areolate thallus, the absence of soredia, the absence of a prothallus, apothecia size, and ascospore size ( Brodo 1984). However, Lecanora baekdudaeganensis differs from L. imshaugii by a darker thallus (bluish, olivish, or pale brownish gray vs. greenish or yellowish gray), brownish disc (vs. reddish brown disc), K-insoluble granules on the surface of epihymenium (vs. absence of granules), a shorter hypothecium (15-25 μm vs. 50-75 μm), and the presence of oil droplets in the apothecial section ( Brodo 1984).

The new species is distinguishable from L. chionocarpa by a darker thallus (bluish, olivish or pale brownish gray vs. ash gray), the absence of a prothallus (vs. presence of white prothallus), crystals in the amphithecium not dissolving in K (vs. granular crystals dissolving in K), a shorter hymenium (50-75 μm vs. 75-100 μm), the presence of oil droplets in hypothecium, subhymenium and the base of hymenium (vs. oil droplets present in epihymenium), shorter asci (41-51 × 13-20 μm vs. 60-70 × 13-18 μm), smaller ascospores (10-18.5 × 4.5-9.5 μm vs. 15-20 × 8-11 μm), thinner ascospore walls (0.5 μm vs. 0.5-1 μm), and the Pd- reaction of the thallus and medulla (vs. Pd+ yellowish) ( Hue 1915; Miyawaki 1988).

The new species differs from L. horiza by a darker thallus (bluish, olivish or pale brownish gray vs. yellowish white to whitish gray), and the crystals in amphithecium not dissolving in K (vs. crystals dissolving in K) ( Smith et al. 2009).

The new species differs from L. japonica by thallus color (bluish, olivish or pale brownish gray vs. dirty greenish to ashy gray), the absence of a prothallus (vs. prothallus with white bundle of hyphae), larger apothecia (0.2-1.6 mm vs. up to 1 mm), a thicker amphithecium (60-100 μm laterally and 110-130 μm basally vs. 5-20 μm laterally and 20-50 μm basally), the presence of oil droplets in hypothecium, subhymenium and the base of hymenium (vs. oil droplets present in epihymenium), shorter hymenium (50-75 μm vs. 70-80 μm), a shorter subhymenium (20-40 μm vs. 180-220 μm), a granular epihymenium (vs. non-granular epihymenium), shorter (41-51 μm) and constantly 8-spored asci (vs. longer (50-80 μm) and 8- or 16-spored asci), the Pd- reaction of the thallus and medulla (vs. Pd+ pale brown thallus and medulla), and the absence of chloroatranorin (vs. presence of chloroatranorin) ( Nylander 1891; Miyawaki 1988; Guderley and Lumbsch 1999).

The new species differs from L. megalocheila by a darker thallus (bluish, olivish or pale brownish gray vs. whitish gray or whitish with green tinge without brownish color), the absence of a prothallus (vs. blackish prothallus), crystals in the amphithecium not dissolving in K (vs. crystals dissolving in K), a shallower hypothecium (15-25 μm vs. 120-150 μm), wider asci (41-51 × 13-20 μm vs. 35-50 × 10-14 μm), larger ascospores (10-18.5 × 4.5-9.5 μm vs. 10-14 × 5-8 μm),, and the Pd- reaction of the thallus and medulla (vs. Pd+ pale yellow thallus and medulla) ( Hue 1915; Miyawaki 1988).

Figures

Figure 4. Lecanora baekdudaeganensis (BDNA-L- 0000065, holotype) in morphology. A-C Habitus with dark thallus and epruinose apothecia D sessile apothecia with constricted base in section. Hypothecial base closed by medulla of amphithecium E well-developed amphithecium with small calcium oxalate crystals (red arrows) not dissolving in KOH F apothecial section in Iodine. I- reaction in the beginning then turning slowly to blue or purple-blue hymenium G oil droplets (red arrows) present in the apothecial section H anastomosing paraphyses shown in Lactophenol cotton blue I asci in hymenium J epihymenium with yellowish granules not dissolving in KOH K-M 8 - spored, clavate asci (M in Lactophenol cotton blue) N, O ellipsoid ascospores in diverse development stages. Spores biguttulate in the beginning then having a long oil drop by assembly of guttules when mature P old pycnidia without pycnocodidia. Scale bars: 200 μm (A, D), 2 mm (B, C), 20 μm (E, G-J), 50 μm (F), 10 μm (K-O), 100 μm (P).