Micarea eurasiatica Kantelinen & G. Thor, 2024

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 eurasiatica Kantelinen & G. Thor sp. nov.

Fig. 3 A, B

Type.

Japan, Honshu, Gunma Prefecture, Katashina-mura, Nikko National Park, 4.7 km E of Marunuma Kogen Ski Resort , 550 m S of the parking lot at the start of the trail up to the summit of Mt. Oku-Shirane, along the trail. Open forest with mainly deciduous trees. On Tsuga diversifolia log. 36.81573 ° N, 139.37823 ° E (± 10 m), elevation 1791 m. 2019. Thor 40053 (Holotype UPS). DNA sample A 914 .

Description.

Thallus endoxylic. Photobiont micareoid, 4–7 µm.

Apothecia few, immarginate, convex, black, matt, 0.1–0.2 mm in diam. Hymenium 25–40 µm tall, hyaline or tinged green, K + greenish when tinged, sometimes with darker vertical streaks. Epihymenium black to blackish-green, K + green, HNO 3 + purple (Cinereorufa-green). Asci clavate, 28–38 × 11–14 µm. Ascospores ellipsoid to ovoid, simple, (6 –) 7–9 × 3–4 µm. Paraphyses numerous, of two types: 1. evenly distributed, branched, thin, c. 0.7–1.5 µm wide, 2. evenly distributed, stout, sometimes branched, 2–3 µm wide, not always coated in pigment. Hypothecium c. 35–45 µm tall, dark brown, K – (Superba-brown), or sometimes with a slight purple tinge (Melaenida-red), hyphae coated with dark brown pigment. Excipulum not evident.

Mesopycnidia few to abundant, sessile to emergent, cylindrical in shape, 50–80 (– 100) µm tall, 30–45 µm wide, black, walls greenish black, K + green, HNO 3 + purple (Cinereorufa-green), sometimes merged from base, usually extruding white mass of conidia that sometimes merge with neighbouring conidial mass. Mesoconidia ellipsoid-cylindrical, (4 –) 4.5–6.0 × 1.2–1.5 (– 1.8) µm. Micro- or macropycnidia not seen.

Chemistry. Material not sufficient for TLC.

Crystalline granules not present in apothecia or pycnidia.

Habitat and distribution.

M. eurasiatica is currently known from Finland and Japan. In Finland, the species was collected in a shaded and dense, Picea abies dominated managed forest. In Japan, the species occurred in a semiopen forest with mainly deciduous trees. On both occasions, the species was found growing on dead wood.

Notes.

M. eurasiatica is currently known from two collections. The type collection has abundant mesopycnidia, and additionally few small apothecia. The other collection has only pycnidia. The most important diagnostic characters are the combination of sessile to emergent pycnidia that are cylindrical in shape, greenish-black pycnidial walls, large mesoconidia (up to 6 µm in length) and a K + olive green reaction (Cinereorufa-green). If apothecia are present, they are 0.1–0.2 mm wide, have greenish-black epihymenium (K + green, Cinereorufa-green) and dark brown hypothecium (K – or sometimes slightly K + purple if Melaenida-red present). Micarea eurasiatica resembles other often asexual Micarea species on dead wood such as M. melaeniza , M. misella , M. olivacea and M. osloensis . Micarea eurasiatica differs from M. melaeniza by having shorter mesopycnidia, longer mesoconidia ( M. melaeniza : (3 –) 3.5–4.5 × 1.2–1.8 µm, M. eurasiatica : (4 –) 4.5–6.0 × 1.2–1.5 (– 1.8) µm), and a more greenish black wall colouration in the pycnidia with no brown tones. Micarea misella has a K + violet reaction (Sedifolia-grey) instead of K + olive green and its mesopycnidia are brownish-black and taller ( Coppins 1983; Czarnota 2007). Micarea olivacea has rather similar short mesopycnidia that react K + green, but the wall of pycnidia is olive-brown and the mesoconidia are shorter than those of M. eurasiatica ( M. olivacea : 3.4–4.3 × 1.2–1.6 µm, M. eurasiatica : (4 –) 4.5–6.0 × 1.2–1.5 (– 1.8) µm) ( Coppins 1983). Micarea osloensis , on the other hand, has a warm brown wall colouration and usually no K reaction.

Additional specimen studied.

Finland, Uusimaa, Tuusula, W of Korso , shaded and dense Picea abies dominated managed forest (plot 2), on wood of fallen Picea abies (decay stage 2), 60.3544 ° N, 25.0322 ° E, 2013, Kantelinen 2729 (DNA A 466), H .

Figures

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.