Verrucaria subjunctiva Nyl., Flora 67: 218, 1884

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 subjunctiva Nyl., Flora 67: 218, 1884

=? Verrucaria lacerata Servít, Stud. Bot. Čech. 11: 115, 1950. Type. Slovakia, Tatry Bielské, rup, calc. pr. Tatranská kotlina, 800 m alt., 1925 Suza (PRM-859169!, syntype)

Type.

[Russia,] Sibiria Septentrionalis: Si nus Konyam ad fretum Bering, 64°50' lat. bor., 173° long. occid. (Greenw.) 28-30.7.1879 E. Almquist (S-L46!, lectotype, designated here); Fretum Behring, Kongar Bay, E. Almquist (H-NYL 3512!, isolectotype).

Description.

Prothallus absent. Thallus white or grey, rarely pale ochraceous, endolithic or thinly epilithic, continuous or rimose, up to 0.1 mm thick, algal cells 5-8 mm. Perithecia (0.16-)0.23-0.45 mm in diam., (1/4-)1/2-3/4(-1)-immersed, not leaving pits or usually leaving shallow or deep pits in the rock, sometimes covered by a thin thalline layer except for the apex, often surrounded by a thalline collar; ca. (10-)30-100(-120) perithecia/cm2. Ostiole tiny, pale or dark, plane or depressed, ca. 20-40(-50) mm wide, ostiolar depression rarely wide, up to 130 mm wide. Involucrellum exceeding half of the exciple or reaching the exciple base level, rarely enveloping the exciple, (40-)50-100 mm thick, appressed to the exciple or slightly to moderately diverging from the exciple. Exciple 0.20-0.36 mm in diam., wall dark brown or black, ca. 22-45 mm thick. Periphysoids ca. 30-60 × (1-)1.5-2.5 mm, branching. Asci 84-109 × 32-40 mm, 8-spored. Ascospores 0-septate, rarely very few spores 1-septate, (23.4-)27.0-30.4-33.8(-40.1) × (11.7-)12.6-13.8-15.0(-17.4) mm (n = 242), perispore 1-2 mm thick.

Habitat and distribution.

The species occurs on calcareous rocks in both sun-exposed and shady sites. Most sequenced specimens are from the biogeographical province of Koillismaa. Three sequenced specimens (two localities) originate from eastern Finland (biogeographical Province of Pohjois-Karjala) and three (two localities) from southern Finland (biogeographical Province of Varsinais-Suomi). In southern Finland, the species seems to be very rare. Verrucaria subjunctiva has not been collected in Finland from lime quarries.

Other specimens examined.

Finland. Varsinais-Suomi, Länsi-Turunmaa (Korppoo), Åfvensår, Kilamo, calcareous rock outcrop, on flat rock, scarce, 17 m. alt., 60°17'N, 21°32'E, 28 July 2009, J. Pykälä 35326 (H); Länsi-Turunmaa (Korppoo), Åfvensår, Kilamo, calcareous rock outcrop, on flat rock, on pebbles, 17 m alt., 60°17'N, 21°32'E, 28 July 2009, J. Pykälä 35361 (H); Salo (Kisko), Haapaniemi, Plantmaannokka, calcareous rock outcrop on shore of Lake Määrjärvi, on calcareous boulder, 43 m alt., 60°12'N, 23°31'E, 4 June 2010, J. Pykälä 37746 (H); Koillismaa, Kuusamo, Oulanka National Park, Pikkukönkäänkuru, dolomite rock outcrop, on SW-facing wall, 173 m alt., 66°21'N, 29°19'E, 8 Aug 2009, J. Pykälä 35930 (H); Kuusamo, Oulanka National Park, Kiutaköngäs, N-shore of river Oulankajoki, dolomite rock outcrop, on SE-slope, 150 m alt., 66°22'N, 29°20'E, 12 Aug 2009, J. Pykälä 36308 (H); Salla, Oulanka National Park, 400 m N of Savilampi, shore of river Savinajoki, cliff, dolomite rock outcrop, on NW-facing wall, 177 m alt., 66°25'N, 29°10'E, 13 Aug 2009, J. Pykälä 36371 (H); Kuusamo, Juuma, Lammasvuoma, gorge, calciferous (dolomite) schistose rock outcrop, on NE-facing wall, 225 m alt., 66°16'N, 29°26'E, 8 Aug 2010, J. Pykälä 39475 (H), 39478 (H), 39491 (H); Salla, Oulanka National Park, Savilamminniemi, shore of lake Savilampi, cliff, dolomite rock outcrop, on E-facing wall, scarce, 185 m alt., 66°25'N, 29°10'E, 12 Aug 2010, J. Pykälä 39803 (H); Kuusamo, Oulanka National Park, Kiutaköngäs, by the rapids, shore of Oulankajoki river, calciferous (dolomite) schistose rock outcrop, N-slope, on boulder, 152 m alt., 66°22'N, 29°20'E, 18 Aug 2010, J. Pykälä 40284 (H); Kuusamo, Juuma, Oulanka National Park, Hautaniitynvuoma, gorge, dolomite rock outcrop, on high NE-facing wall, very scarce, 190 m alt., 66°15'N, 29°26'E, 21 Aug 2011, J. Pykälä 44671 (H); Kuusamo, Juuma, Oulanka National Park, Hautaniitynvuoma, gorge, stony NW-slope with sparse stunted birches, close to bottom, on dolomite boulder, 181 m alt., 66°15'N, 29°26'E, 21 Aug 2011, J. Pykälä 44734 (H); Salla, Oulanka National Park, Savilampi 1.2 km NE, steep E-slope, open area in forest, on small dolomite rock, 190 m alt., 66°26'N, 29°11'E, 23 Aug 2011, J. Pykälä 44881 (H); Pohjois-Karjala, Juuka, Polvela, Valkealampi, close by E-shore, Pinus sylvestris -dominated forest, calcareous rock outcrop, on W-slope, 176 m alt., 63°10'N, 29°07'E, 11 July 2011, J. Pykälä 42392 (H), 42419 (H); Juuka, Polvela, Valkealampi, close by E-shore, Pinus sylvestris -dominated forest, calcareous rock outcrop, W-slope, directly on rock, rather scarce, 175 m alt., 63°10'N, 29°07'E, 11 July 2011, J. Pykälä 42406 (H); Juuka, Petrovaara, Riihilahti S, shore of lake Polvijärvi, calcareous rock outcrop, on W-facing wall, 171 m alt., 63°09'N, 28°58'E, 13 July 2011, J. Pykälä 42510 (H).

Notes.

This species has usually been treated as V. papillosa Ach. and was also reported from Finland as V. papillosa ( Pykälä 2010a). However, Orange (2004b) showed that the type specimen of V. papillosa belongs to V. viridula (Schrad.) Ach. The type specimen of V. lacerata is small, but it fits rather well with the Finnish material. However, ITS sequences from Central Europe are needed to confirm the identity of V. lacerata . According to Breuss (2008b), the exciple size in V. lacerata is 0.4-0.6 mm, i.e. exceeding the size of V. subjunctiva . The ITS phylogeny does not separate V. subjunctiva from V. foveolata . These two taxa are here kept separated pending further study (see V. foveolata ). Verrucaria subjunctiva and V. foveolata have larger spores than the other studied species. However, there is much overlap in the spore size of V. devergens and V. kuusamoensis and specimens with suboptimally-developed spores are easily misidentified. Verrucaria subjunctiva has larger perithecia and longer periphysoids than V. kuusamoensis .