Ochrolechia incarnata (Leight.) Kukwa, Schmitt & Ertz, 2018

Kukwa, Martin, Schmitt, Imke & Ertz, Damien, 2018, Ochrolechia incarnata comb. nov. (Lecanoromycetes, Ascomycota), a distinct species of the O. parella group from Europe and Macaronesia, Phytotaxa 371 (2), pp. 119-126 : 122-124

Ochrolechia incarnata (Leight.) Kukwa, Schmitt & Ertz comb. nov. MycoBank no 826952

Basionym. Pertusaria incarnata Leighton (1878 (‘1877’): 241).

Type:—[ IRELAND, South-east Galway ( V.C. H.15),] Kylemore, Aug. 27 [18]75, CL. no. 20 [C. Larbalestier] (holotype BM!).

( Fig. 2 )

Thallus thin to thick, cracked, areolate, folded or rugose; areoles crowded, brownish, light brown, yellow-grey, grey or grey-white, often tops of areoles more greyish or finely white pruinose; soralia and isidia absent; prothallus indistinct or as white zone at the thallus margin; apothecia up to 3 mm in diam., sessile, rounded or irregular in shape; thalline margin well developed, raised above the disc, even or flexuose, smooth, rough or radiately striate, shiny or matt, usually concolorous with or lighter than the thallus; margin cortex well developed, up 100 μm wide in the upper part, expanded at the base up to 200 μm; thalline margin medulla well differentiated; excipulum proprium clearly visible in section, present as a thin excipular ring between the disc and thalline margin, in section up to 100 μm in upper part; disc ± plane or concave, flesh coloured to red-brown, usually heavily white pruinose, sometimes with sterile thalline tissues; pruina granular, white, forming a thin or usually thick layer; algal layer well developed, as groups of algal cells in excipulum and below hypothecium or more rarely forming continuous layer; hypothecium yellowish; hymenium up to 250 μm high, hyaline, I+ blue, KI+ blue; paraphyses numerous, richly branched and anastomosing towards epihymenium, not distinctly enlarged at the apex, apex hyaline; asci clavate, with thick wall and thicker apical wall without recognizable structures, I+ blue, KI+ blue, usually abortive, (4–)8-spored; ascospores widely ellipsoidal or ellipsoidal, rarely subglobose, 40–75 × 25–49 μm; conidiomata not seen; photobiont trebouxioid.

Chemistry: substances detected in apothecia: gyrophoric (+, major to minor), lecanoric (+, minor or trace), olivetoric (+, major, minor or sometimes as trace), alectoronic (±, major to minor) and variolaric (+, major) acids, also ‘microstictoides unknowns’ (±, traces) and traces of unidentified pigments (±, traces) most probably connected with gyrophoric acid (see Kukwa 2011). Substances detected in thallus: variolaric acid (+, major) and ‘microstictoides unknowns’ (±, traces). Spot test reactions of apothecia: apothecial margin cortex K–, C+ yellowish or yellow, apothecial margin medulla C+ red or orange-red, KC+ red, disc pruina K–, C–, epihymenium C+ red (sometimes the reaction is very faint and more easily seen in mature apothecia). Spot test reactions of thallus: medulla C–, KC–, cortex K–, C+ yellowish or yellow. All parts of thallus UV ± glaucous or negative.

Distribution and habitat: Ochrolechia incarnata has been found in Europe ( Ireland, Sweden) and Macaronesia (Canary Islands, Porto Santo). The species seems to be common in the Canary Islands, and rare elsewhere, however, all O. parella collections from western and northern Europe were not reexamined for this study and it may appear to be more common there after such work is carried out.

Hanko et al. (1986) reported a chemotype of O. parella with olivetoric acid (as ‘Stoffmuster C’) from the Canary Islands; most probably this record also belongs to O. incarnata .

The species always grows on non-calcareous rocks, mostly in sun-exposed places with xerophytic and shrubby vegetation.

Notes: Ochrolechia incarnata is characterised by the saxicolous habit, pruinose apothecial discs, the presence of variolaric acid in cortex of apothecia and thallus, gyrophoric acid in epihymenium and olivetoric acid in apothecial margin medulla.

The type of Pertusaria incarnata ( Fig. 2A ) is small with only few immature apothecia. The margin medulla shows the distinct C+ red reaction, however TLC analyses of one small immature apothecium yielded no olivetoric acid. As sometimes we detected only trace of olivetoric acid in other specimens, even if the apothecial margin showed a strong C+ red reaction, we believe that the absence of this substance on the chromatograms is due to the too low concentration of it in the type material.

Ochrolechia incarnata is morphologically identical with O. parella and has been treated as a synonym of the latter ( Kukwa 2011). Both species share the same substances and spot test reactions, however the apothecial margin medulla in O. incarnata reacts C+ red supposedly due to the production of olivetoric acid. In addition, they form two separate and well supported monophyletic clades ( Fig. 1 ).

Ochrolechia antarctica is also morphologically and chemically very similar to O. incarnata , but, like O. parella , it lacks olivetoric acid. According to Ertz et al. (2016) O. antarctica is only distantly related to O. parella (Ertz et al. 2016) and thus also to O. incarnata , which is phylogenetically the most closely allied species to O. parella ( Fig. 1 ). Moreover, O. antarctica is known from southern South America and Antarctica (Ertz et al. 2016).

The C+ red reaction of the margin medulla and pruinose apothecial discs are known also in the O. africana -group ( Brodo 1991), of which O. africana Vainio (1926: 3) sometimes may grow on rocks ( Kukwa et al. 2013). The C reaction of the margin medulla in this species is, however, due to the presence of methylated hiascic acids rather than olivetoric acid ( Brodo 1991). Moreover, the O. africana -group and O. incarnata are allopatric ( Brodo 1991; Kukwa 2011; Kukwa et al. 2013).

Some extra-European species also produce olivetoric acid, e.g., O. subpallescens Verseghy (1962: 118) , but they always lack variolaric acid ( Brodo 1991).

Additional specimens examined. EUROPE. IRELAND, Kerry (Ciarrai), Corca Dhuibhne Dingle-Halbinsel, Umgebung des Weilers Ballyoughteragh N Baile an Fheirtearaigh , August 1978, J. Poelt s.n. ( GZU). SWEDEN, Västergötland , Falköping , Vilhelmsro , on rock, August 1935, E. P. Vrang s.n. (S F-93883). MACARONESIA. SPAIN. CANARY ISLANDS. El Hierro , W of Sabinosa, W of Montaña del Escobar, W slope, 27°45’11”N, 18°08’39”W, elev. 270 m, field with volcanic outcrops, on volcanic rock, 25 August 2009, D. Ertz 13574 ( BR) ; Fuerteventura, Morro de la Cruz (vor Betancuria ), on rock, 02 March 1990, J. Müller-Lütken s.n. (B 74728) ; Gran Canaria, Tafira ( Lava ), elev. ca. 400 m, on rock, April 1901, J. Bornmüller, Bornmüller, Pl. Exs. Canar. 3389 ( WRSL) ; La Palma, Flores , 28°31’N, 17°49’W, elev. 760 m, lava flow, on rock, 26 March 1978, J. O. Juvik L-6 (B 142217) ; Lanzarote, Los Helechos N ober dem Dorf Maguez, am SE-Rand des Kraters , 29°10’20”N, 13°29’55”W, elev. 500 m, NW-exponiert and Basaltschrofen , 6 April 1999, A. Hafellner & J. Hafellner 47608 ( GZU) ; Tenerife, Anaga Mts, El Bailadero , 28°32’59”N, 16°12’19”W, elev. 680 m, open area, rocks by the road, on rock, 28 November 2016, R. Szymczyk s.n. ( OLS, UGDA) ; NW-side of island, Montana de Tacos, small crater N of San Bernardo, E of Buenavista , elev. 280 m, xerophylic scrub, on rock, 19 April 1978, H. Sipman 9500 (B 109282) ; El Meson, on ridge along San Andres Valley, Sierra de Anaga , elev. 350 m, lower xerophilous zone, saxicolous, H. A. Imshaug 35774 & F. H. Imshaug (B 600109283) ; grossflächig an halbschattigen luftfeuchten Kulm- und Stirnflächen grobkörniger Lavarippen im Roccelastrum canariensis, elev. 250 m, Roque de los Enamorados östlich Taganana am Nordabfall der Anagahalbinsel, March 1977, G. Follmann & G. White, Follmann, Lich. Exs. 232 (B, H, GZU). PORTUGAL. Porto Santo, Pico do Facho , elev. 450 m, small exposed rock, on rock, 6 April 2007, D. Ertz 10572 ( BR) .

Figures

FIGURE 2. Ochrolechia incarnata. A, holotype of Pertusaria incarnata; B, close up of the thallus of the holotype; C–D, morphology of apothecia and thallus (Ertz 10572). Scale bars: C = 1 mm, D = 500 μm.

FIGURE. 1. Phylogenetic relationships among 25 samples of Ochrolechia inferred from Bayesian analysis of nuITS sequences. Posterior probabilities are shown above internal branches, and Maximum Likelihood bootstrap values obtained from a RAxML analysis are shown below internal branches. Internal branches strongly supported in both analyses, are represented by thicker lines.The clade of O. incarnata, a species resurrected here, is highlighted. Corticolous samples of O. parella are marked with an asterisk (*).