Protoblastenia rupestris (Scop.) J. Steiner

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 rupestris (Scop.) J. Steiner , Verh. Kaiserl.-Königl. zool.-bot. Ges. Wien 61: 47 (1911)

Lichen rupestris Scop., Fl. carniol., Edn 2 ( Wien) 2: 363 (1772).

Description.

Thallus whitish-grey to rarely pale brown, rimose to predominantly areolate, areoles 0.1–0.8 mm, ca. 0.1–0.2 mm thick, K-, C-, UV- to UV + bluish-white, algal cells 4–12 μm. Apothecia yellow-orange to orange, 0.2–0.9 mm, slightly convex to convex, 3 / 4 - immersed in thallus to superficial; ca. 40–100 apothecia / cm 2. Epihymenium orange-brown, 12–20 μm thick, K + violet. Hymenium 50–80 μm thick. Hypothecium pale yellow, ca. 60–80 μm thick. Paraphyses ca. 1.5–2.5 μm thick, apex not thickened to slightly thickened to 2–3 μm thick, sparingly branched and anastomosing. Ascospores 0 - septate, (8.2 –) 9.1–10.3 – 11.6 (– 13.0) × (5.2 –) 5.6–6.3 – 7.1 (– 7.6) μm (n = 43).

Habitat and distribution.

Sequenced specimens were collected from rather sun-exposed calcareous rock outcrops in the hemi-boreal zone in Finland. The species may prefer calcareous rock outcrops close to shores.

Notes.

Protoblastenia rupestris sequences available in GenBank are heterogeneous and distributed in three different groups in our ITS phylogeny (Fig. 1 ). Specimens similar to those in Kainz and Rambold (2004) are likely to belong to P. rupestris s. stricto as the species was described from Central Europe. The sequence MZ 159571 ( UK) is related to P. incrustans and the sequence KY 266981 ( Norway) belongs in P. rikkinenii . Morphologically, the Finnish specimens of P. rupestris may be confused with the closely-related P. borealis . However, the P. rupestris specimens have a predominantly areolate thallus, while the thalli of P. borealis are more often rimose and usually do not exceed 0.1 mm in thickness. Furthermore, P. borealis often has a thicker hypothecium. Despite these minor differences, the two species often cannot be distinguished with certainty by morphology only.

Specimens examined.

Finland • Varsinais-Suomi, Lohja, Skraatila, Kirkkovuori E , cliff, calcareous rock outcrop, on S-slope, 8. 8. 1990, J. Pykälä 5963 ( H) ; • Lohja, Lohja, Pitkäniemi industrial area, by the sauna, on shore of Lohjanjärvi Lake , flat calcareous rock outcrop, 33 m a. s. l., 60°15'N, 24°02'E, 19. 8. 2005, J. Pykälä 27569 ( H) ; • Karjalohja, Saarenpää, Saarenpäänniemi , calcareous rock outcrop on shore of Lohjanjärvi Lake, on small SW-facing wall, 35 m a. s. l., 60°13'N, 23°47'E, 7. 10. 2008, J. Pykälä 34043 ( H) ; • Salo (Särkisalo), Kaukosalo, Klintinmäki , cliff, calciferous schistose rock outcrop, on SW-facing wall, st pc, 35 m a. s. l., 60°06'N, 22°58'E, 4. 10. 2011, J. Pykälä 46413 ( H) .

Figures

Figure 1. Phylogenetic relationships of the studied Protoblastenia species, based on a Maximum Likelihood (ML) analysis of the ITS dataset. Maximum likelihood bootstrap values > 50 % are shown at nodes. Thickened lines indicate bootstrap values > 70 %. New species described in this study are indicated with shadowed boxes. GenBank accession numbers for sequences downloaded from GenBank and collection numbers for the specimens sequenced for this study are shown after the taxon names. Holotype specimens of the new species are shown in bold.