Verrucaria grossa Nyl., in Nylander & Saelan, Herb. Mus. Fennici 111, 1859

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 grossa Nyl., in Nylander & Saelan, Herb. Mus. Fennici 111, 1859

Type.

[Russia,] Lapponia Rossica, 1843, F. Nylander (H!, holotype or syntype).

Description.

Prothallus not seen. Thallus grey, rimose. Perithecia ca. 0.4-0.6 mm, 1/2-immersed, leaving deep pits in the rock. Involucrellum enveloping the exciple, ca. 50-100 mm thick, thicker at apex. Exciple ca. 0.3-0.4 mm in diam., wall black. Ascospores in very poor condition, 0-septate, ca. 22-25 × 10 mm.

Notes.

The specimen in H is small and in a very poor condition. Vainio (1921) reported the spore size of 15-24 × 10-18 mm. Pykälä (2010b) reported the species new to Finland. The Finnish specimen (the sequencing failed) may be rather similar to the one sectioned perithecium of the type of V. grossa , which, however, had spores in poor condition. Verrucaria grossa should be treated as a species with unresolved identity unless better type material can be located.