Buellia epigaea (Pers.) Tuck. Gen. lich.: 185 (1872)

Ai, Min, Li, Li Juan, Worthy, Fiona Ruth, Yin, An Cheng, Zhong, Qiu Yi, Wang, Shi Qiong, Wang, Li Song & Wang, Xin Yu, 2022, Taxonomy of Buellia epigaea - group (Caliciales, Caliciaceae), revealing a new species and two new records from China, MycoKeys 92, pp. 45-62 : 45

Buellia epigaea (Pers.) Tuck. Gen. lich.: 185 (1872)

Fig. 7

Type.

Germany. Hesse, ad terram inter muscos non procul a Monte Meissner, 1794, Persoon (H-Ach-Isotype, not seen) .

Description.

Thallus terricolous, tightly attached to the substrate, upper surface white or greyish white, usually with white fine pruina, thallus crusty, uneven to wrinkled, 0.2-1 mm thick, prothallus absent; the upper cortex 60-150 µm thick, with granular crystals, pith completely interspersed with Ca oxalate crystals; medulla white. Apothecia sparse to dense, lecideine, but usually surrounded by a thalline collar (pseudolecanorine); disc black, always with finely white pruina, roundish, 0.5-1.0 mm in diam., mostly flat, rarely slightly convex; young apothecia immersed and margin with finely white pruina breaking out broadly, mature apothecia adnate and margin absent or not obvious; exciple Buellia aethalea -type, up to 50 µm thick, without aeruginose pigments (HNO3-); epihymenium brown to dark brown; hymenium hyaline, 60-80 µm tall, without oil droplets, paraphyses simple to moderately branched, apically swollen, with a brown pigment cap; hypothecium hyaline to light brown, up to 100 µm high; asci oval-clavate, Bacidia -type, eight-spored; spores 1-septate, hyaline when young, turning brown when mature, with tapering ends, Callispora -type, often curved, not thickening during spore ontogeny, 12-20 × 6-10 µm. Pycnidia not seen.

Chemistry.

Thallus K-, C-, KC-, PD-, UV-; without secondary metabolites.

Distribution and ecology.

This species mainly occurs on open and dry soil, soil within meadows or on soil over rock, between elevations of 2300-4700 m. This species has been recorded in Asia, Europe and North America ( Trinkaus and Mayrhofer 2000). In China, it is mainly distributed in Gansu, Qinghai and Xizang Provinces.

Note.

The species is a new record for China; it could be distinguished from all the other terricolous Buellia species reported in China by the combination of the following characteristics: thallus white crustose, uneven to wrinkled, always covered by finely white pruina, apothecia pseudolecanorine, the ornamentation of the ascospore surface densely areolate and rough, pycnidia rare, Callispora -type ascospores and absence of secondary metabolites. This species is close to Tetramelas species in phylogeny and similar in morphology, but could be distinguished by absence of the secondary metabolites 6-O-methylarthothelin or related xanthones, and pseudolecanorine apothecia covered with white pruina.

Selected specimens examined.

China. Gansu Prov.: Sunan Co., along the route from Linze to Sunan , on soil over rock, 38°52'26"N, 99°44'21"E, alt. 2294 m, 29 May 2018, L.S. Wang et al. 18-58766; Sunan Co. , along the route from Linze to Sunan, on soil over rock, 38°52'47"N, 99°43'57"E, alt. 2296 m, 29 May 2018, L.S. Wang et al. 18-59699 . Qinghai Prov.: Gonghe Co., meadow beside Qinghai Lake , on soil within meadow, 36°33'26"N, 100°28'45"E, alt. 3431 m, 18 May 2018, L.S. Wang et al. 18-59162 . Xizang Prov.: Qushui Co., Niedang Vil., on soil, 29°30'24"N, 90°56'17"E, alt. 3527 m, 22 Jul. 2019, X.Y. Wang et al. XY19-1234; Qushui Co., Niedang Vil., on soil over rock, 29°30'22"N, 90°56'15"E, alt. 3624 m, 22 Jul. 2019, X.Y. Wang et al. XY19-1218; Langkazi Co. , entrance to Karuola Glacier, on soil over rock, 28°53'54"N, 90°13'32"E, alt. 4774 m, 24 Jul. 2019, X.Y. Wang et al. XY19-2294 .

Figures

Figure 7. Morphology of Buellia epigaea (XY 19 - 2294 KUN) A thallus growing on the soil B lecideine apothecia with white pruina, surrounded by a thalline collar (pseudolecanorine) C the section of apothecium, exciple Buellia aethalea - type D ascospores with 1 - septate, Callispora - type E ascus Bacidia - type. Scale bars: 2 mm (A); 1 mm (B); 50 µm (C); 10 µm (D, E).