Immersaria athroocarpa (Ach.) Rambold & Pietschm., in Rambold, Biblioth. Lichenol. 34: 240 (1989).

Xie, Cong-Miao, Wang, Li-Song, Zhao, Zun-Tian, Zhang, Yan-Yun, Wang, Xin-Yu & Zhang, Lu-Lu, 2022, Revision of Immersaria and a new lecanorine genus in Lecideaceae (lichenised Ascomycota, Lecanoromycetes), MycoKeys 87, pp. 99-132 : 99

Immersaria athroocarpa (Ach.) Rambold & Pietschm., in Rambold, Biblioth. Lichenol. 34: 240 (1989).

Figure 4a-e

Type.

Sweden [no locality, no date, no collector], H9508237 (H-Ach-lectotype!-designated in Hertel 1977). High-resolution photographs seen.

Description.

Thallus areolate, yellow-brown, orange-brown, continuous; areolae 0.2-1.0 mm across, often convex, regular polygons, tends to be squamalose at the margin, epruinose; margin pruinose; prothallus black, not distinct, sometimes absent. Upper cortex ca. 32.0 μm thick, yellow-brown; epinecral layer ca. 7.0 μm thick; algal layer ca. 82.0 μm thick, cells 8.0-10.0 × 7.5 μm in diam., ellipsoid. Apothecia frequent, densely crowded, immersed, 0.3-1.3 mm in diam.; disc black, rare pruinose, flat, epruinose; margin reduced. Exciple sometimes developed, 25.0-30.0 μm wide, brown. Hymenium 100-115 μm thick, colourless; paraphyses 1.0-2.0 μm wide, branched, not anastomosing; epihymenium 20.0-25.0 μm thick, brown, rarely green; subhymenium ca. 90.0 μm thick, colourless; hypothecium pale brown to brown. Asci Porpidia -type, cylindrical, eight-spored; ascospores 17.5-20.0 × 10.0 μm, ellipsoid, halonate. Conidiomata immersed, stellate, black, margin pruinose; conidia 7.5-10.0 × 1.0 μm in diam., bacilliform.

Chemistry.

Thallus K-, C-. Medulla I+ violet. Chemotype Ⅰ: Confluentic acid. Chemotype Ⅱ: Unknown substance.

Ecology and distribution.

In China, growing on granite in arid and semi-arid steppe habitats at elevations of 1200-1950 m. Worldwide distribution. This species is known from Inner Mongolia and Mt. Changbai ( Hertel and Zhao 1982) in China.

Notes.

The lectotype grows on siliceous rock and contains several intact apothecia. The materials from Inner Mongolia are identical with the lectotype, based on comparisons with high-resolution photographs and the description given by Hertel (1977). It is, therefore, treated as Immersaria athroocarpa at present. Some Inner Mongolian materials contain an unknown substance, but form a well-supported clade with other materials. Immersaria athroocarpa is characterised by the convex, yellow-brown areolae and the large sizes of ascospores. In this genus, only this species has ascospores up to 20.0 μm long.

Immersaria usbekica is similar to I. athroocarpa in its brown thallus and dense apothecia, but differs in its flat areolae, the brown epihymenium and the presence of confluentic acid and gyrophoric acid. By comparison with high-resolution photographs and the original descriptions ( Hertel 1977) of Immersaria usbekica , we discovered that previous reports of this species from China ( Zhang et al. 2015) were due to misidentification. It is known from Algeria, Iran, Spain, and the USSR ( Barbero et al. 1990).

Specimens examined (SDNU).

China. Inner Mongolia: Chifeng City, Balin Youqi, Hongshilazi , 1403.2 m elev., 44°13'N, 118°44'E, on rock, 2019, Ling Hu et al. SDNU20190035; Rongshen, Wangfengou, 1217.4 m elev., 44°16'N, 118°22'E, Ling Hu et al. SDNU20190140, SDNU20190143; Erlinba, 1915.2 m elev., 44°26'N, 118°41'E, Ling Hu et al. SDNU20190227 .

Figures

Figure 4. Immersaria athroocarpa (a-e SDNU 20190227): a-b thallus c apothecial anatomy d ascus e ascospores. I. aurantia (f-j KUN XY 19 - 1290): f-g thallus h apothecial anatomy i ascus j ascospores. Scale bars: 1 mm (a-b, f-g); 20 μm (c, h); 10 μm (d-e, i-j).