Micarea nigella Coppins

Kantelinen, Annina, Svensson, Måns, Malíček, Jiří, Vondrák, Jan, Thor, Göran, Palice, Zdeněk, Svoboda, Stanislav & Myllys, Leena, 2024, A phylogenetic study of Micarea melaeniza and similar-looking species (Pilocarpaceae) unveils hidden diversity and clarifies species boundaries and reproduction modes, MycoKeys 106, pp. 327-353 : 327-353

Micarea nigella Coppins

Fig. 3 E, F, G

Micarea nigella Coppins. Bull. Brit. Mus. Nat. Hist. 11 (2): 163 (1983). Type: Denmark, Jylland, c. 16 km N of Hobro, Rold Skov, Torstedlund Skov, on conifer stump, lignum, 1979, Coppins 4429 ( RBGE! – holotype).

Description.

Thallus endoxylic or thin green-grey layer on top of substrate. Photobiont micareoid, 4–7 µm.

Apothecia absent to numerous (mostly rare), immarginate, subglobose, often becoming tuberculate, black, matt, 0.1–0.3 mm in diam. Hymenium 25–30 µm tall, hyaline or tinged dull brown or purplish brown, K + sordid green, HNO 3 + purple-red (Melaena-red), often with darker vertical streaks. Epihymenium irregularly pigmented brown to purplish-brown (Melaena-red), sometimes dark greenish, K + olive green, HNO 3 + purple (Cinereorufa-green). Asci clavate, 22–30 × 10–12 µm. Ascospores ellipsoid to usually ovoid, simple, 6.5–12 × 2.5–4.0 µm. Paraphyses of two types: 1.) evenly distributed, branched, thin, c. 0.7–1 µm wide, 2.) scattered or in small fascicles, stout, 2–3 µm wide, coated by dark pigment. Hypothecium c. 70–120 (– 160) µm tall, dark brown with variable amount of purplish tone, K + olive green, HNO 3 + purple-red (Melaena-red), hyphae coated with a dark brown pigment. Excipulum not evident.

Mesopycnidia always present, usually numerous, black, sessile or more usually stalked and then 80–300 µm tall, 40–80 µm in diam., stalks simple or branched from the base bearing up to four pycnidia, walls brownish black to purplish black, sometimes olivaceous from the top, K + dull green and HNO 3 + purple-red especially in the brown parts (Melaena-red). Mesoconidia ellipsoid or short cylindrical 3.5–4.5 (– 5) × 1.2–1.8 µm. Micro- or macropycnidia not seen.

Crystalline granules not present in apothecia, pycnidia or thallus.

Chemistry no substances detected by TLC (information based on Coppins 1983 and Czarnota 2007).

Habitat and distribution.

Micarea nigella occurs mainly on lignum of conifer stumps or fallen trunks, sometimes spreading from wood to dead bryophytes. Based on sequenced specimens and the type material, the species is known from the Czech Republic, Denmark (holotype), Great Britain (paratypes), Finland and Sweden. In addition, M. nigella has previously been reported from boreal and temperate forests in north-western, central and eastern Europe (e. g. Czarnota 2007).

Notes.

In external appearance, M. nigella resembles M. melaeniza . The differences between these two species are discussed in detail under M. melaeniza and Coppins (1983). The species also resembles M. botryoides , M. misella and M. osloensis . Micarea botryoides is usually not lignicolous and prefers rain-sheltered microhabitats on various substrata, it has slightly taller pycnidia (up to 400 µm) and longer ascospores (8–13 (– 16) × 2.3–4 µm) that are often septate (e. g. Coppins 1983). Microscopically, M. misella can be distinguished by the olivaceous pigment that reacts violet instead of dull green in K, and by its hyaline hypothecium ( Coppins 1983; Czarnota 2007). Micarea osloensis , on the other hand, is usually K – and its pycnidia are shorter. However, our study includes specimens that are difficult to identify by morphological characters, especially between M. melaeniza , M. nigella and M. osloensis .

One of the distinguishing characteristics of M. nigella is the Melaena-red pigment (K + green, HNO 3 + purple-red) in the hymenium, hypothecium and pycnidia. In the literature, the pigment is described as`purple` ( Coppins 1983; Meyer and Printzen 2000; Czarnota 2007). However, based on our study, the pigment is mostly brown, sometimes with a purplish tinge. The holotype of M. nigella has the Melaena-red pigment, that looks brown with a purplish tinge, but of our three sequenced specimens (Fig. 2 , Table 1 ), one (collection Kantelinen 1971) has no purplish tone, whereas the other two collections (Kantelinen 1974, 1921) have easily detected amounts of purple. Interpreting the colouration can be difficult and confusing, but maybe a helpful hint is that the pigment is always K + green, even if it looks brown in water. According to our study, the K + green reaction mostly disappears in 30 minutes.

Occasionally, M. nigella also has a third pigment, the Melaenida-red (K + purple). This pigment was not found in the Finnish specimens but is sometimes seen in the Central European specimens included in this study and mentioned also by Coppins (1983) and Czarnota (2007). The Melaena-red and Melaenida-red pigments can be intermixed and appear in varying concentrations.

Additional specimens studied.

Czech Republic, Central Bohemia, Brdy Protected Landscape Area, Míšov, Na Skalách Nature Reserve, old-growth beech forest, small scree with rock outcrops and sparse spruce forest in NW part of the protected area, 49 ° 36 ' 20 " N, 13 ° 45 ' 56 " E, 715–740 m, on stump, 2023, Malíček 16287, hb Malíček. Western Bohemia, Domažlice, Český les Protected Landscape Area, Pec, Bystřice Nature Reserve, natural mixed forest up to 150 years old, 49 ° 22 ' 56 " N, 12 ° 48 ' 39 " E, 650–750 m, on lying decaying trunk, 2015, Malíček 8029 (hb Malíček); ibid., Tachov Lesná: managed spruce forest 1 km NE of Knížecí strom Hill (829 m), 49 ° 46 ' 13.0 " N, 12 ° 29 ' 28.3 " E, 750 m, on stump of Picea abies , 2019, Malíček 13161 & Rydlo, hb Malíček. Southern Bohemia, Prachatice, Šumava National Park, Nová Pec old-growth beech-spruce forest on N-facing slope of Mt Hraničník (1281 m), 48 ° 45 ' 13 " N, 13 ° 54 ' 17 " E, 1170 m, on decaying wood, 2017, Malíček 11296, hb Malíček. Eastern Bohemia, Žďár nad Sázavou, Žďárské vrchy Protected Landscape Area, Svratka managed beech-spruce forest on NW-facing slope of Bubnovaný kopec Hill (780 m), 49 ° 42 ' 41.6 " N, 16 ° 05 ' 13.7 " E, 775 m, on stump of Picea abies , 2020, Malíček 13865 & Sejfová, hb Malíček. Svratka forest mosaic 0.2 km SSE of Spálený kopec Hill (766 m), 49 ° 43 ' 28.0 " N, 16 ° 06 ' 23.3 " E, 755 m, on stump of Picea abies , 2020, Malíček 13868 & Sejfová, hb Malíček. Svitavy, Česká Třebová, Psí kuchyně Nature Reserve, old-growth beech forest 0.1 km NW of Psí kuchyně Hill (526 m), 49 ° 50 ' 38.3 " N, 16 ° 26 ' 47.5 " E, 505 m, on lying wood of Fagus sylvatica , 2020, Malíček 13975 & Rydlo, hb Malíček. Silesia, Beskydy Protected Landscape Area, Horní Lomná, Velký Polom Nature Reserve, valley of a brook with old-growth, beech predominated forest in the E part of the protected area, 49 ° 30 ' 36 " N, 18 ° 41 ' 00 " E, 860–910 m, on stump of Picea abies , 2021, Malíček 14664 & Sejfová, hb. Malíček; ibid., gorge on NW-facing slope of Mt Velký polom (1067 m), c. 49 ° 30 ' 25 " N, 18 ° 40 ' 04 " E, 950–1000 m, on stump, 2021, Malíček 14649, Hlisnikovský & Sejfová, hb Malíček; ibid., Karolinka, Malý Javorník Nature Reserve, old-growth spruce-beech forest, 49 ° 18 ' 20.9 " N, 18 ° 17 ' 18.5 " E, 880–970 m, on wood of stump, 2023, Malíček 16392, hb Malíček; ibid., Valašská Bystřice, Kutaný Nature Reserve, old-growth beech-silver fir forest, 49 ° 22 ' 15.6 " N, 18 ° 6 ' 0.4 " E, 610–770 m, on fallen wood, 2020, Malíček 14246 & Konečná, hb Malíček. Jeseníky Protected Landscape Area, Karlova Studánka, old-growth spruce forest on SE-facing slope in valley of Bílá Opava Brook, along tourist path 1.1 km NE of Ovčárna, 50 ° 04 ' 37 " N, 17 ° 15 ' 06 " E, 1170–1200 m, on roots of Picea abies , 2015, Malíček 8547, hb. Malíček.

Finland, Pohjois-Karjala, Lieksa, Koli National Park (plot 9), East side, old-growth forest, on wood of fallen Picea abies (decay stage 2), 63.1033 ° N, 29.8140 ° E, 2013, Kantelinen 1971 (DNA A 589), H; ibid., Kantelinen 1974 (DNA A 588), H; ibid., Kantelinen 1921 (DNA A 572), H. Etelä-Häme, Hämeenlinna, Evo (plot 8), protected old managed forest, on wood of a Picea abies stump (decay stage 5), 61.2088 ° N, 25.1363 ° E, 2013, Kantelinen 2851 (DNA A 769), H; ibid., Kantelinen 2881 (decay stage 4, DNA A 764), H.

Slovakia, Eastern Slovakia, Bukovské vrchy Mts., Nová Sedlica, protected area Stužica, NNE-facing slope of Temný vršok Mt. (838 m), old-growth beech forest, 49 ° 04 ' 11 " N, 22 ° 32 ' 26 " E, 750–820 m, on stump of Abies alba, 2013, Malíček 6511 & Vondrák, hb Malíček.

Figures

Figure 2. Bayesian tree of the Micarea melaeniza - group and similar-looking species based on mtSSU and ITS sequences. Bayesian posterior probabilities are always indicated near the branches together with bootstrap support when less than 80 (e. g. 0.70 / 63).

Figure 3. Morphological and anatomical features A, B Micarea eurasiatica sp. nov. (Thor 40053) A habit B apothecial section in water C, D Micarea melaeniza (Holotype) C habit, apothecia and pycnidia D apothecial section in water E – G Micarea nigella (Holotype) E apothecial section in K F apothecial section in water G drawing of M. nigella pycnidia on dead wood (Kantelinen 1974, H), Ga.) Mesopycnidia extruding mesoconidia, Gb.) Mesoconidia are cylindrical, ellipsoid, sometimes biguttulate. Photos and drawing Kantelinen. Scale bars: Habit 0.5 mm (A, C); Apothecial sections 100 µm (B, C, E, F); Drawing Ga 100 µm, Gb 1 µm.