Acarospora pyrenopsoides H.Magn, 1926

Westberg, Martin, Timdal, Einar, Asplund, Johan, Bendiksby, Mika, Reidar Haugan,, Jonsson, Fredrik, Larsson, Per, Odelvik, Goeran, Wedin, Mats & Millanes, Ana M., 2015, New records of lichenized and lichenicolous fungi in Scandinavia, MycoKeys 11, pp. 33-61 : 35-36

Acarospora pyrenopsoides H.Magn, 1926

Acarospora pyrenopsoides H.Magn. Acta Horti Gothob. 2: 74. 1926.

Holotype.

GREENLAND. Nennese. [undated], J. Vahl ( UPS L-067474!).

Distribution.

New to Norway and Sweden. This is another poorly known species that has received very little attention since Magnusson (1926) discovered it. It has until now been known from scattered records from Greenland, Germany, Finland and Austria ( Magnusson 1935, Wirth et al. 2013). It has also been reported from Denmark and Canada but those finds are considered erroneous ( Søchting and Alstrup 2008, Knudsen and Kocourková 2010). This is a characteristic species that has a thallus composed of rounded, fairly large squamules (fertile squamules 0.5-3 mm wide), with an incised or almost lobate margin (Fig. 2 ). The upper surface is flattened with a brownish grey colour. The lower side as well as the steep, vertical sides of the squamules are jet black and somewhat shiny. The apothecia are immersed, at first deeply sunken but later almost level with the thallus. The disc is brown, somewhat shiny and can become somewhat uneven in larger apothecia. Magnusson (1926) thought that the apothecia resembled those in certain species of Pyrenopsis from which the epithet is derived. The diagnostic characters include a thin poorly delimited cortex (10-15 µm), an uninterrupted algal layer, a tall (120-140 µm), euamyloid (I+ blue), hymenium and narrow spores (4-5 × 1.5 µm). Acarospora pyrenopsoides is a peculiar Acarospora not similar to any other species in the genus. Magnusson (1926) considered its position in the genus to be isolated because of its unusual characters but speculated that it may be closest to A. nitrophila . The specimen from Norway was sequenced and a preliminary analysis (not shown) indicates that it belongs to a group with A. peliscypha , A. molybdina and A. wahlenbergii within Acarospora in a restricted sense (see Westberg et al. 2015). There is however, as far as we can see, no particular character of its morphology that indicates this relationship.

Acarospora pyrenopsoides appear to prefer humid localities. The locality in Norway reported here, lies near a waterfall where the species was found on sloping rocks. It is the only European site of the North American Rhizocarpon bolanderi (Tuck.) Herre, and was found during an inventory of that species. The two Swedish localities are located on or near lakeshores in the province of Värmland in central Sweden.

Specimens examined.

NORWAY. Aust-Agder: Valle, Hallandsfossen. 28 July 2010, Timdal 11308 ( O L-163369); SWEDEN. Värmland: Stora Kil par., W steep towards the lake Fryken, S of Prästhamna. 15 May 1960, Sundell 1915a ( UPS L-126715); Trankil par., Guppviksön. 22 Aug. 1976, Sundell 11217 ( UPS L-515137).

Figures

Figure 2. Acarospora pyrenopsoides (O L- 163369). Scale: 1 mm.