Protoblastenia borealis Pykälä & Myllys, 2025

Pykälä, Juha & Myllys, Leena, 2025, Unexpected species richness of the lichen genus Protoblastenia (Lecanorales, Psoraceae) in Finland, MycoKeys 124, pp. 193-226 : 193-226

Protoblastenia borealis Pykälä & Myllys sp. nov.

Fig. 2 B

Diagnosis.

Differs from P. rupestris in having a mostly rimose thallus.

Type.

Finland • Varsinais-Suomi, Lohja, Lylyinen, Sääksniemi , N of summer cottages, small calcareous rock outcrop, on SW-slope, 50 m a. s. l., 60°15'N, 23°57'E, 16 September 2003, J. Pykälä 23710 ( H 9250905 – holotype, UPS – isotype, GenBank accession number: PV 766638 ) .

Description.

Thallus white to pale grey, endolithic (rarely), rimose (usually) to areolate, areoles 0.1–0.8 mm, ca. 0.02–0.2 mm thick, K-, C-, UV- to UV + bluish-white, algal cells 5–12 (– 17) μm. Apothecia yellow-orange to dirty brown-orange, 0.2–1.0 mm, slightly convex to strongly convex, ½ - immersed in thallus to superficial, occasionally leaving shallow pits, K + violet; ca. 30–140 apothecia / cm 2. Epihymenium orange-brown, 10–18 μm thick, K + violet. Hymenium 50–90 (– 100) μm thick. Hypothecium colourless to pale yellow, rarely lower part reddish-brown, occasionally with oil droplets, ca. 40–160 μm thick. Paraphyses ca. (1.5 –) 2–2.5 μm thick, apex not or slightly thickened, sparingly branched and anastomosing. Ascospores 0 - septate, (7.6 –) 9.6–11.2 – 12.7 (– 16.1) × (4.8 –) 5.4–6.2 – 7.0 (– 7.7) μm (n = 146).

Habitat and distribution.

This species is the most common species of Protoblastenia in Finland. It occurs from the hemi-boreal zone to middle Lapland. It grows on calcareous and calciferous rocks on both sun-exposed and shady habitats, but may prefer the latter. It also often grows in lime quarries. Specimens from concrete probably also belong in this species, but no sequences of them are available. Typical companion species include, for example, Acarospora glaucocarpa (Ach.) Körb. , Clauzadea monticola (Schaer.) Hafellner & Bellem. , Farnoldia jurana (Schaer.) Hertel , Lathagrium fuscovirens (With.) Otálora, P. M. Jørg. & Wedin , Phaeophyscia sciastra (Ach.) Moberg , Scytinium parvum (Degel.) Otálora, P. M. Jørg. & Wedin , Verrucaria deversa Vain. , V. epilithea Vain. , V. muralis Ach. and V. nigrescens Pers.

Etymology.

The name refers to the geographic distribution of the species in the boreal vegetation zone.

Notes.

Protoblastenia borealis is morphologically very variable and may differ in the size and density of apothecia and in the thickness of the hypothecium. The sister species Protoblastenia ekmanii is morphologically similar, but appears to differ in having a thicker hypothecium. The new species is also difficult to distinguish from the closely-related P. rupestris . However, P. rupestris does not have any strongly convex apothecia and has, on average, a thicker thallus, which is mostly areolate. Protoblastenia pseudocompressa often / usually has plane apothecia, but some specimens with convex apothecia are somewhat similar to P. borealis . The two Finnish specimens of Protoblastenia calvella resemble P. borealis in morphology; they have strongly convex apothecia and a thick hypothecium which were also observed in a few P. borealis specimens. Due to these overlaps, ITS is needed for unambiguous identification of P. borealis .

Other sequenced specimens.

Finland • Varsinais-Suomi, Karkkila, Haavisto, Herneojankallio , pyroxene gneiss rock outcrop, on high SW-facing overhanging wall, scarce, 80 m a. s. l., 60°29'N, 24°20'E, 18. 5. 1996, J. Pykälä 16567 ( H) ; • Lohja, Torhola, 300 m N-NE of Kallioranta , young pine plantation, S-slope, almost 1 m high rock wall of calcareous rock outcrop, rather scarce, 60 m a. s. l., 60°15'N, 23°52'E, 22. 7. 2004, J. Pykälä 25292 ( H) ; • Karjalohja, Karkali, 200 m SW Karkali farm, on a shore of Lohjanjärvi Lake , small calcareous rock outcrop, on stone, 33 m a. s. l., 60°14'N, 23°49'E, 19. 10. 2004, J. Pykälä 26097 ( H) ; • Pohja, Kuovila , 300 m SW of Vihreämäki , abandoned lime quarry, NE-facing wall, 37 m a. s. l., 60°08'N, 23°24'E, 12. 10. 2006, J. Pykälä 29704 ( H) ; • Suomusjärvi, Sallittu, Huuttavanmäki , calciferous rock outcrop, on W-facing wall, 110 m a. s. l., 60°18'N, 23°37'E, 28. 6. 2008, J. Pykälä 32757 ( H) ; • Särkisalo, Förby, E of Vähämaankaula , abandoned lime quarry, on N-facing wall, 7 m a. s. l., 23. 7. 2008, J. Pykälä 33037 ( H) ; • Särkisalo, Förby, E of Vähämaankaula , abandoned lime quarry, on NW-facing wall, 7 m a. s. l, 23. 7. 2008, J. Pykälä 33101 ( H) ; • Kemiönsaari (Västanfjärd), Finsjö, Verkviksudden , calcareous rock outcrop, on 1.2 m high E-facing wall, 5 m a. s. l., 60°00'N, 22°41'E, 13. 7. 2010, J. Pykälä 38784 ( H) ; • Salo (Suomusjärvi), Hinttala, W of Kalattomansuo , Picea abies - dominated herb-rich forest, abandoned lime quarry, on S-facing wall, 110 m a. s. l, 60°23'N, 23°39'E, 28. 9. 2010, J. Pykälä 41355 ( H) ; • Etelä-Savo, Kerimäki, Ruokojärvi, Pitkäniemi , close by abandoned lime quarry, young Pinus sylvestris - forest, on calcareous boulder, 90 m a. s. l., 61°56'N, 29°00'E, 15. 9. 2011, J. Pykälä 45759 ( H) ; • Pohjois-Karjala, Juankoski, Siikajärvi, Huosiaisniemi, Nature Reserve , mixed herb-rich forest, dolomite rock outcrop, on W-facing wall, scarce, 100 m a. s. l., 63°12'N, 28°21'E, 25. 7. 2011, J. Pykälä 42802 ( H) ; • Juankoski, Siikajärvi, Lauantaijoki, Kalliola 250 m N , calciferous serpentine rock outcrop, on NW-facing wall, 132 m a. s. l., 63°09'N, 28°36'E, 9. 9. 2013, J. Pykälä 47217 ( H) ; • Keski-Pohjanmaa, Vimpeli, Sääksjärvi, Huosianmaankallio , lime quarry, quarry spoil, on calcareous boulder, rather scarce, 135 m a. s. l., 63°09'N, 24°04'E, 1. 9. 2010, J. Pykälä 40695 ( H) ; • Kainuu, Hyrynsalmi, Moisiovaara, Hyyryläinen SW , Pinus sylvestris - dominated heath forest, VMT site type, calciferous serpentine rock outcrop, on 1 m high W-facing wall, 190 m a. s. l., 64°32'N, 29°05'E, 30. 5. 2021, J. Pykälä 57501 ( H) ; • Koillismaa, Kuusamo, Oulanka National Park, Kiutaköngäs 400 m N , Pinus sylvestris - herb-rich forest, small dolomite rock outcrop, on SE-slope, rather scarce, 175 m a. s. l., 66°22'N, 29°19'E, 3. 8. 2010, J. Pykälä 39151 ; • Kuusamo, Juuma, Oulanka National Park, Hautaniitynvuoma , gorge, calciferous (dolomite) schistose rock outcrop, on SW-facing wall, 195 m a. s. l, 66°15'N, 29°27'E, 14. 8. 2010, J. Pykälä 39942 ( H) ; • Kuusamo, Juuma, Oulanka National Park, Hautaniitynvuoma , gorge, NE-slope, calciferous (dolomite) schistose rock outcrop, on NE-facing wall, 179 m a. s. l., 66°15'N, 29°26'E, 21. 8. 2011, J. Pykälä 44641 ( H) ; • Salla, Oulanka National Park, Savilampi 1.4 km NE, bank of Savinajoki River , cliff, dolomite rock outcrop, on SE-facing wall, 185 m a. s. l., 66°26'N, 29°11'E, 23. 8. 2011, J. Pykälä 44906 ( H) ; • Kuusamo, Kallunki, Juhonlampi , young Pinus sylvestris - dominated heath forest, calcareous rock outcrop, SW-slope, on 80 cm high SW-facing wall, 236 m a. s. l., 66°22'N, 29°03'E, 5. 8. 2021, J. Pykälä 58196 ( H) ; • Kuusamo, Vasaraperä, Havukkalampi N , mixed herb-rich heath forest, calcareous rock outcrop, on 100 cm high SW-facing wall, 246 m a. s. l., 66°06'N, 28°44'E, 8. 8. 2021, J. Pykälä 58392 ( H) ; • Kittilän Lappi, Kittilä, Tepsa, Herravaara SE , clear-cut heath forest, small calcareous rock outcrop, on 1.5 m high SE-facing wall, scattered, 15. 9. 2022 J. Pykälä & I. Kuusisto 60511 ( H) .

Figures

Figure 2. A. Protoblastenia arupii (holotype); B. P. borealis (holotype); C. P. compressa (holotype); D. P. dolomitica (holotype). Scale bars: 0.5 mm.