Protoblastenia lilacina Poelt & Vězda

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 lilacina Poelt & Vězda , Čas. slezsk. Mus. Opavě, Ser. A 19: 26 (1970)

Description.

Thallus white to grey, endolithic, farinose to small areoles, K-, C-, UV- to UV + bluish-white, algal cells 3–8 μm. Apothecia orange to dark orange, 0.2–0.6 mm, slightly convex to strongly convex, 1 / 4 - immersed to superficial, sometimes leaving shallow pits, K- or K + fairly weakly red; ca. 40–100 apothecia / cm 2. Epihymenium (yellowish) orange-brown, 12–20 μm thick, K- to K + orange or carmine red, not into solution. Hymenium 50–120 μm thick, with oil droplets. Hypothecium pale yellow, sometimes patchily violet, ca. 60–120 μm thick. Paraphyses ca. 2–3 μm thick, apex not thickened to slightly thickened, sparingly branched and anastomosing. Ascospores 0 - septate, (8.4 –) 10.7–12.4 – 14.2 (– 16.6) × (5.2 –) 6.0–6.7 – 7.3 (– 7.8) μm (n = 30).

Habitat and distribution.

The species is rare and occurs only on calcareous rock outcrops and boulders in the hemi-boreal zone in SW Finland. This seems to be the northern limit of this predominantly temperate species. Protoblastenia lilacina grows both on fairly sun-exposed and shady habitats. It may prefer rather dry calcareous rocks. Companion species include, for example, Bagliettoa baldensis s. lat, B. calciseda (DC.) Gueidan & Cl. Roux , Catillaria lenticularis (Ach.) Th. Fr. , Hymenelia spp. , Lecidella stigmatea (Ach.) Hertel & Leuckert , Staurothele rupifraga (A. Massal.) Arnold , Verrucaria deversa Vain. , V. foveolata and V. viridula .

Notes.

The species differs from most species of Protoblastenia in having K- or weakly K + red apothecia. The closely-related Protoblastenia oulankaensis is the only other species with this characteristic. However, the two species have different distribution areas as Protoblastenia oulankaensis is only known from the Oulanka area in NE Finland. Morphologically, P. oulankaensis differs in having a thicker hypothecium and often more sparsely occurring apothecia (in most specimens 10–30 apothecia / cm 2).

Specimens examined. Finland • Varsinais-Suomi, Kemiönsaari (Västanfjärd), Vesterillo, Strömmen 200–400 m SE , Pinus sylvestris - dominated forest, calcareous rock outcrop, on 70 cm high E-facing wall, 17 m a. s. l., 60°00'N, 22°44'E, 9. 9. 2009, J. Pykälä 37012 ( H) ; • Lohja, Moisio, between Lohjanharjuntie and Nummentie roads, NW-slope of Lohjanharju esker , Pinus sylvestris - heath forest, on calcareous boulder, 82 m a. s. l., 60°15'N, 24°06'E, 18. 6. 2005, J. Pykälä 27009 H ); • Lohja, Lohja, Pitkäniemi industrial area, 5 m from shore of Lohjanjärvi Lake , deciduous forest, calcareous rock outcrop, on NW-facing 2 m high rock wall, 35 m a. s. l., 60°15'N, 24°02'E, 19. 8. 2005, J. Pykälä 27629 ( H) ; • Lohja, Lohja, Pitkäniemi industrial area, deciduous forest ca. 5 m from shore of Lohjanjärvi Lake , calcareous rock outcrop, on 1.7 m high overhanging NW-facing wall, 35 m a. s. l., 60°15'N, 24°02'E, 12. 7. 2021, J. Pykälä 57976 ( H) .