Micarea azorica van den Boom, Guzow-Krzeminska , Brand & Serus .

Guzow-Krzeminska, Beata, Serusiaux, Emmanuel, van den Boom, Pieter P. G., Brand, A. Maarten, Launis, Annina, Lubek, Anna & Kukwa, Martin, 2019, Understanding the evolution of phenotypical characters in the Micarea prasina group (Pilocarpaceae) and descriptions of six new species within the group, MycoKeys 57, pp. 1-30 : 1

Micarea azorica van den Boom, Guzow-Krzeminska, Brand & Serus. sp. nov. Fig. 2B

Diagnosis.

Species characterised by pale to moderately brownish thallus consisting of goniocysts, convex to subglobose, emarginate, pale greyish-brown to dark brown (with Superba-brown pigment) apothecia measuring 0.1-0.3 mm in diam., (0-)1-septate, narrowly ellipsoidal to ovoid ascospores measuring 9-11 × (2.5 –)3– 4 µm, sessile to slightly stalked, pale to moderately brown mesopycnidia, bacillar mesoconidia measuring 6.5-8 × 0.9-1.1 µm and the production of micareic acid.

Type.

Portugal. Azores, Terceira, NW of Angra do Heroismo, south edge of Reserva Florestal da Lagoa das Patas, area around a pond 'Lagoa das Patas’, 520 m alt., 38°43.01'N, 27°17.32'W, mature Cryptomeria trees and Camellia shrubs, on Cryptomeria japonica , 28 June 2014, P. & B. van den Boom 51468 (holotype LG; isotypes UGDA, hb v.d.Boom, mtSSU GenBank accession number: MK562026, Mcm7 GenBank accession number: MN105891).

Description.

Thallus inconspicuous, thinly scurfy to somewhat farinose-granular, pale to moderately brownish and consisting of goniocysts; prothallus not seen; apothecia abundant, convex to subglobose, emarginate, pale greyish-brown to dark brown, often unevenly coloured in a single apothecium (partly dark, partly pale), 0.1‒0.3 mm in diam.; hymenium ca. 32‒40 µm tall; epihymenium with grey-brown pigment, K‒, C‒ (Superba-brown); hypothecium hyaline; paraphyses, abundant, branched, ca. 1.0 –1.5(– 1.8) µm wide, tips not widened and not pigmented; asci 25-35 × 11-14 µm, 8-spored; ascospores narrowly ellipsoidal to ovoid, (0-)1-septate, 9-11 × (2.5 –)3– 4 µm; mesopycnidia occasionally abundant, sessile to slightly stalked, 40-60 µm in diam., pale to moderately brown, the ostiole sometimes gaping; mesoconidia bacillar, simple, 6.5‒8 × 0.9‒1.1 µm; crystalline granules (studied in polarised light) visible in epithecium and in thallus, soluble in K.

Photobiont micareoid, cells thin-walled, 4-10 µm in diam., clustered in compact groups.

Chemistry.

Micareic acid detected by TLC. Superba-brown in apothecia (epihymenium).

Habitat and distribution.

To date, known only from the Azores archipelago (Terceira island) from three localities where it was found on bark of trees.

Etymology.

The name refers to the archipelago of the Azores, where the species occurs.

Additional specimens examined.

Portugal. Azores, Terceira, NW of Angra do Heroismo, Reserva Florestal Viveira da Falca, 460 m alt., 38°42.90'N, 27°16.78'W, picnic area with many mature Cryptomeria trees, some Acer trees and Camellia , on Cryptomeria , 28 June 2014, P. & B. van den Boom 51330 (hb. v.d. Boom); N of Serreta, Reserva Florestal da Serreta, 80 m alt., 38°46.27'N, 27°21.42'W, picnic area in open forest with mixed trees and shrubs, on tree, 2 July 2014, P. & B. van den Boom 51733 (hb. v.d. Boom).

Notes. The new species is resolved as sister to M. prasina s.str. with strong support, being morphologically and chemically similar to that species, but differing in the absence of the Sedifolia-grey pigment, responsible for the typical reaction K+ violet in M. prasina s.str ( Coppins 1983; Czarnota 2007; Launis et al. 2019a). Instead of Sedifolia-grey pigment, Superba-brown is present in M. azorica .

The identity of M. prasina s.str. has been recently solved by Launis et al. (2019a, b) and its occurrence is confirmed from boreal and temperate Europe (Finland, Germany, Poland) and Eastern North America (Canada: New Brunswick and USA: Maine) ( Launis et al. 2019b; this paper). Other records need confirmation as, previously, other species have been included in the variation of M. prasina .

Micarea azorica resembles M. lithinella (Nyl.) Hedl. due to its brownish, convex to subglobose small apothecia, but the latter is mainly a saxicolous species, has smaller conidia, 4‒5.5 × 0.5‒1 µm and does not contain secondary metabolites ( Coppins 1983; Czarnota 2007).

Figures

Figure 2. Morphology of newly described Micarea species A M. aeruginoprasina (holotype) B M. azorica (holotype) C M. isidioprasina (holotype) D M. microsorediata (holotype) E M. nigra (holotype) F M. pauli (holotype). Scale bars: 200 µm (A−C, E); 300 µm (D, F).