Protoblastenia ekmanii 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 ekmanii Pykälä & Myllys sp. nov.

Fig. 3 A

Diagnosis.

Differs from P. borealis in having a thicker hypothecium.

Type.

Finland • Varsinais-Suomi, Salo (Kisko), Kirkonkylä, 450 m NW of Kolko, shore of Määrjärvi Lake , calcareous rock outcrop, on W-slope, 43 m a. s. l., 60°12'N, 23°31'E, 20 May 2010, J. Pykälä 37508 ( H 9224071 – holotype, GenBank accession number: PV 766674 ) .

Description.

Thallus white to greyish-white, rimose to areolate, areoles 0.3–0.6 mm, ca. 0.05–0.2 mm thick, K-, UV + bluish-white, algal cells 5–8 μm. Apothecia dirty brown-orange, 0.4–0.8 mm, convex to strongly convex, superficial; ca. 30–50 apothecia / cm 2. Epihymenium dark orange-brown, 10–20 μm thick, K + violet. Hymenium 50–70 μm thick. Hypothecium yellowish-white, ca. 120–200 μm thick, in some apothecia base patchily red-violet. Paraphyses ca. 2–2.5 μm thick, apex not or slightly thickened. Ascospores 0 - septate, (8.1 –) 8.7–10.2 – 11.6 (– 12.5) × (5.0 –) 5.1–5.9 – 6.6 (– 7.2) (n = 12).

Habitat and distribution.

Only one specimen is known from a calcareous rock outcrop on a lake shore in SW Finland. The sun-exposed site suggests that the species may have a southern distribution. The species is apparently very rare in Finland. Companion species include Acarospora glaucocarpa , Clauzadea monticola , Placynthium nigrum (Huds.) Gray and Thelidium incavatum .

Etymology.

The name is in honour of Dr Stefan Ekman ( Uppsala) for his many important contributions on the phylogeny and taxonomy of lichens in Fennoscandia and elsewhere.

Notes.

The species is closely related to P. borealis (only 2.5 % difference in ITS), but seems to differ in having a thicker hypothecium. The hypothecium of P. borealis is very variable, but in no specimens does it reach the upper limit of the thickness in the P. ekmanii specimen. The Finnish specimens of P. calvella have orange-yellow to orange apothecia and thus resemble P. ekmanii . More material is needed to determine whether the species can be unambiguously morphologically distinguished from P. calvella .

Figures

Figure 3. A. Protoblastenia ekmanii (holotype); B. P. fennoarctica (holotype); C. P. minuta (holotype); D. P. oulankaensis (holotype). Scale bars: 0.5 mm.