Protoblastenia westbergii Pykälä & Myllys sp. nov.

Fig. 5 D

Diagnosis.

Differs from P. dolomitica in having slightly broader spores, darker orange apothecia and a thicker hypothecium.

Type.

Finland • Enontekiön Lappi, Enontekiö, Kilpisjärvi, Saana Nature Reserve, E-part, fell, steep SW-slope, on dolomite boulder, 910 m a. s. l., 69°02'N, 20°51'E, 13 August 2011, J. Pykälä 44316 (H 9229821 – holotype, GenBank accession number: PV 766718) .

Description.

Thallus white to whitish-grey, rimose to areolate, areoles 0.15–0.8 mm, ca. 0.05–0.3 mm thick, K-, C-, UV- to UV + bluish-white, algal cells 4–8 μm, thallus often strongly invaded by cyanobacteria. Apothecia orange to dark brownish-orange, 0.2–1.1 mm, slightly convex to convex, 3 / 4 - immersed to superficial, in one specimen with pale margin ca. 30–50 μm thick; ca. 40–200 apothecia / cm 2. Epihymenium dirty yellow to orange-brown, 10–15 μm thick, K + violet. Hymenium 40–70 μm thick, often with oil droplets. Hypothecium red-brown to red-violet, ca. 60–150 μm thick. Paraphyses ca. 2–2.5 μm thick, apex not thickened to slightly thickened to 3 μm thick, some branched and anastomosing. Ascospores 0 - septate, (8.4 –) 10.5–12.0 – 13.6 (– 15.0) × (5.0 –) 5.4–6.1 – 6.9 (– 7.8) μm (n = 39).

Habitat and distribution.

Four specimens are known from the calcareous Saana and Toskalharji fells in NW Finland. On Saana, both specimens occurred close to each other on a steep SW-slope on a dolomite boulder. On Toskalharji, the species was found on a SE-facing slope on dolomite pebbles. The species may prefer dry, sun-exposed habitats. Companion species include Farnoldia jurana, Parmeliella thriptophylla (Ach.) Müll. Arg., Thelidium auruntii and Verrucaria sp.

Etymology.

The name is in honour of Dr Martin Westberg (Uppsala) for his important work on the taxonomy and biogeography of northern European lichens.

Notes.

The species is closely related to P. dolomitica (4 % difference in ITS). Protoblastenia dolomitica has, on average, smaller and paler, sometimes olive-yellow apothecia, narrower spores and a thinner hypothecium. However, P. westbergii often also has a thin hypothecium. Protoblastenia arupii has slightly broader spores, a thin hypothecium and possibly thinner thallus.

Other specimens examined.

Finland • Enontekiön Lappi, Enontekiö, Porojärvet, Toskalharji, Toskaljärvi N, fell, dolomite scree, gentle SE-slope, on dolomite pebbles, 715 m a. s. l., 69°11'N, 21°26'E, 2. 8. 2011, J. Pykälä 43196 (H) ; • Enontekiö, Porojärvet, Toskalharji, Toskaljärvi N, fell, dolomite rock outcrop, SE-slope, on dolomite pebbles, 720 m a. s. l., 69°12'N, 21°26'E, 2. 8. 2011, J. Pykälä 43279 (H) ; • Enontekiö, Kilpisjärvi, Saana Nature Reserve, E-part, fell, steep SW-slope, on dolomite boulder, 910 m a. s. l., 69°02'N, 20°51'E, 13. 8. 2011, J. Pykälä 44314 (H) .