Verrucaria foveolata ( Floerke ) A. Massal., Ric. auton. lich. crost.: 346, 1852

Pykaelae, Juha, Kantelinen, Annina & Myllys, Leena, 2020, Taxonomy of Verrucaria species characterised by large spores, perithecia leaving pits in the rock and a pale thin thallus in Finland, MycoKeys 72, pp. 43-92 : 43

Verrucaria foveolata ( Floerke) A. Massal., Ric. auton. lich. crost.: 346, 1852

= Verrucaria latzeliana Servít, Stud. Bot. Čech. 9: 89, 1948. Type. Ragusa: Gartenmauer am 3. Aquidotto, ca. 200 m, Kalk, 28.7.1907, A. Latzel (PRM-859178!, holotype)

Verrucaria schraderi Sommerf. var. foveolata Flörke, Deutschl. Lich. 6, 1815. Basionym.

Type.

Not seen. Protologue: "auf Kalksteinen bei Rüdersdorf”.

Description.

Prothallus absent. Thallus white, grey or pale brown, endolithic, often inconspicuous, rarely thinly epilithic, algal cells 5-9 mm. Perithecia 0.11-0.42 mm, (1/2-)3/4-1-immersed in rock, leaving deep pits in the rock, commonly surrounded by a thallus collar, sometimes covered by a thin thalline layer except for the apex; (30-)60-120 perithecia/cm2. Ostiole usually inconspicuous, tiny, pale or dark, plane or depressed, ca. 20-40(-50) mm wide, wider ostiolar depression rarely present up to 80 mm wide. Involucrellum absent or apical, rarely covering half of the exciple, 40-60 mm thick. Exciple 0.19-0.42 mm in diam., usually round, but sometimes pear-shaped or at least longer than broad, medium brown (rarely), dark brown or black, ca. (20-)25-43(-60) mm thick, apex sometimes thickened to ca. 40-60 mm thick if the involucrellum is absent. Periphysoids ca. (30-)40-65 × 1-2(-3) mm, branching. Asci 78-102 × 27-39 mm, 8-spored. Ascospores 0-septate, rarely solitary spores 1-septate, (23.6-)27.4-30.5-33.7(-37.3) × (10.4-)12.1-13.4-14.6(-17.1) mm (n = 197), perispore 1-1.5 mm thick.

Habitat and distribution.

The species grows on calcareous rocks and in lime quarries, both on sun-exposed and shady rocks, both in southern and in northern Finland.

Other specimens examined.

Finland. Varsinais-Suomi, Lohja, Torhola, 400 m E of Torhola cave, S-slope, calcareous rock outcrop, 40 m alt., 60°15'N, 23°52'E, 20 July 2007, J. Pykälä 31528 (H); Salo (Kisko), Leilä, Kalkuuni, Pinus sylvestris -dominated forest, SW-slope, on calcareous rock wall, 60 m alt., 60°12'N, 23°35'E, 14 July 2009, J. Pykälä 34953 (H); Länsi-Turunmaa (Korppoo), Åfvensår, Kilamo, abandoned lime quarry, on SW-facing wall, 13 m alt., 60°17'N, 21°32'E, 28 July 2009, J. Pykälä 35395 (H); Salo (Kisko), Haapaniemi, Plantmaannokka, calcareous rock outcrop on shore of Lake Määrjärvi, on NE-facing wall, 42 m alt., 60°12'N, 23°31'E, 4 June 2010, J. Pykälä 37728 (H); Salo (Kisko), Jyly, 200 m NE of Purslammi, calcareous rock outcrop, on NW-facing wall, 67 m alt., 60°14'N, 23°36'E, 17 June 2010, J. Pykälä 38119 (H); Kemiönsaari ( Dragsfjärd), Olmos, Kolaskär island, calcareous rock outcrop on shore of the Baltic Sea, beneath SE-facing wall, on pebbles, 2 m alt., 60°03'N, 22°19'E, 12 July 2010, J. Pykälä 38719 (H); Koillismaa, Kuusamo, Oulanka, Putaanoja, 500 m W-NW of Hautala, Pinus sylvestris -dominated semi-open forest, dolomite rock outcrop, on N-slope, 230 m alt., 66°22'N, 29°25'E, 9 Aug 2009, J. Pykälä 35965 (H); Kuusamo, Kallunki, Merenvaara, Pinus sylvestris -dominated forest, NW-slope, small dolomite rock outcrop, on W-facing wall, 225 m alt., 66°20'N, 29°20'E, 2 Aug 2010, J. Pykälä 39028 (H); Kuusamo, Oulanka National Park, Kiutaköngäs 400 m N, SE-slope, Pinus sylvestris -dominated forest, small dolomite rock outcrop, on SW-facing wall, 170 m alt., 66°22'N, 29°19'E, 5 Aug 2010, J. Pykälä 39294 (H); Salla, Oulanka National Park, W of Savikoski, cliff, dolomite rock outcrop, NE-slope, on dolomite boulder, 185 m alt., 66°25'N, 29°10'E, 17 Aug 2010, J. Pykälä 40195 (H); Kuusamo, Oulanka National Park, Taivalköngäs, shore of Oulankajoki river, Picea abies -dominated herb-rich forest, dolomite rock outcrop, NE-slope, on dolomite boulder, 174 m alt., 66°24'N, 29°11'E, 20 Aug 2011, J. Pykälä 44553 (H); Salla, Hautajärvi, Kurtinniittykuru, dolomite rock outcrop, on flat surface, 195 m alt., 66°26'N, 29°09'E, 24 Aug 2011, J. Pykälä 44952 (H).

Notes.

Fennoscandian specimens of Verrucaria with large spores, perithecia leaving deep pits in the rock and immersed in rock, lacking an involucrellum and with endolithic pale thallus have been predominantly treated as V. foveolata (e.g. Foucard 2001). It remains uncertain whether V. foveolata is the correct name for this common species, as the type material was not located. The absence of involucrellum has been used as the main character to separate V. foveolata from morphologically-similar species with apical involucrella, such as V. dolomitica (A. Massal.) Kremp. ( Breuss 2004). However, the sequenced Finnish specimens with an apical involucrellum do not differ from specimens without an involucrellum.

Based on the ITS phylogeny, Verrucaria foveolata and V. subjunctiva are not monophyletic, but together form a strongly-supported group. However, the two taxa are, for the time being, treated as separate species pending further study. Most specimens can be identified by their morphology, although we found some intermediate specimens having morphological characters pointing to both species. However, overlap in the morphology is not larger than compared to several, not closely related species of Verrucaria . Verrucaria foveolata is more difficult to be separated from V. devergens (see the species) than from V. subjunctiva . Furthermore, some ecological and biogeographical differences seem to occur between V. foveolata and V. subjunctiva . Verrucaria subjunctiva has not been found from lime quarries, whereas several populations of V. foveolata occur in lime quarries. Verrucaria foveolata is fairly common on calcareous rocks both in southern and northern Finland, whereas V. subjunctiva is rare in southern Finland.