Verrucaria praecellens (Arnold) Servit , Stud. Bot. Cech . 9: 100, 1948

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 praecellens (Arnold) Servit, Stud. Bot. Cech. 9: 100, 1948

Amphoridium praecellens Arnold, Verh. Zool. Bot. Ges. 19: 651, 1869. Basionym.

Type.

[Italy] 87. Dolomitfelsen in der Schlernklamm ober … in Süd Tirol, 7.1867, Arnold (H-NYL 3208!, H-NYL 3209!, syntypes).

Description.

Prothallus absent. Thallus endolithic, grey with a violet tinge, a dark line between contiguous conspecific thalli present, 0.15-0.22 mm wide. Perithecia 0.21-0.44 mm, immersed in rock, leaving deep pits in the rock. Ostiolar depression large. Involucrellum absent or possibly in some perithecia, small apical involucrellum. Exciple ca. 0.4 mm in diam., apex thickened to ca. 60-80 mm, wall black. Periphysoids ca. 50-60 × 2 mm. Ascospores 0-septate, ca. 26-34 × 16-20 mm, perispore ca. 1-1.5 mm thick.

Notes.

The perithecia of the syntypes in H-NYL are mainly over-mature. The spore size annotated by Nylander to the specimen is larger (40-48 × 23-26 mm) than the few spores measured by us. Servít (1948) reported high variation in the spore size: 20-45 × 18-26 mm. Verrucaria praecellens seems to be characterised by broad spores and a persistent perispore. Verrucaria cryptica has narrower spores. V. praecellens has been synonymised with V. hochstetteri ( Krzewicka 2012), but it may differ by persistent perispores and larger spores.