Lecaimmeria C.M. Xie, Lu L. Zhang & Li S. Wang, 2022

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

Lecaimmeria C.M. Xie, Lu L. Zhang & Li S. Wang gen. nov.

Etymology.

The name " Lecaimmeria " refers to the immersed lecanorine apothecia of all known species.

Type species.

Lecaimmeria orbicularis C.M. Xie & Lu L. Zhang, sp. nov.

Description.

Thallus crustose, red-brown, orange-brown or dark brown, continuous or not; areolae irregular or tending to rectangular, with a glossy surface (atrobrunnea -type) caused by a layer of dead, colourless cells above the upper cortex; margin white or black; prothallus distinct at the margin of thallus or absent, sometimes developed between areolae. Upper cortex orange; epinecral layer colourless; algal layer continuous; medulla filled with grey granules. Apothecia lecanorine, immersed, round or irregular; disc red-brown, dark red-brown or dark orange-brown, flat or concave; margin present or absent, black or white, rarely green, pruinose or not. Exciple reduced, tissue at the lateral sides of the hymenium corresponding to the upper cortex and the algal layer of the vegetative areolae and to hypothecial hyphal cells when apothecia reach the margin of the areole (indicated in Figs 7c, g , 8c , 9c, h , 10c, h ). Hymenium colourless; paraphyses simple, rarely branched, anastomosing or not; epihymeinum orange, orange-brown, rarely brown, with a plectenchyma. Asci Porpidia -type (indicated in Fig. 9d ), cylindrical, eight-spored; ascospores ellipsoid, halonate, non-amyloid. Conidiomata present or absent, immersed, rarely convex, linear or stellate, rarely tuberculiform; conidia bacilliform.

Chemistry.

Thallus K-, C+/-. Medulla I+ violet. Gyrophoric acid, 4-O-demethylplanaic acid or no substances detected by TLC.

Ecology and distribution.

In China, growing on rock, sandstone, granite or Qilian jade (rare), from elevations of 3100 to 4800 m in the alpine zone of west China and from 1200 to 1900 m in the steppe of north China. This genus is known from China, Europe, Iran, Mongolia, Romania, Russia, and USA.

Notes.

The five-loci phylogenetic analysis showed that the species with lecanorine apothecia formed a novel lineage and should be excluded from Immersaria ; thus, they are here treated as a new genus Lecaimmeria . Lecaimmeria is distinguished from related genera by its glossy surface, orange or red-brown areolae with margins, the amyloid medulla, the red-brown immersed lecanorine apothecia, the orange epihymenium with a plectenchyma and the Porpidia -type asci with eight halonate and non-amyloid ascospores. In China, the genus is distributed in alpine areas, high altitude desert-steppe areas or high latitude steppe. Almost all the species of Lecaimmeria grow on granite or sandstone, with the exception of one species, L. tuberculosa , which grows on jade. Interestingly, the margin of conidiomata and areolae of Lecaimmeria tuberculosa appear with heavily jade-green pruinose.

The immersed apothecia and brown thallus of Lecaimmeria often resemble those of Immersaria , but Lecaimmeria differs in its red-brown lecanorine apothecia, often with a white margin, their orange epihymenium with a plectenchyma and the thallus containing gyrophoric acid. This genus might be confused with Bellemerea by its lecanorine apothecia and the Porpidia -type asci with halonate ascospores, but the latter genus differs in its amyloid ascospores.

Three species, previously included in Immersaria , I. cupreoatra , I. iranica and I. mehadiana , have lecanorine apothecia, but two of these, I. cupreoatra and I. mehadiana , currently lack molecular sequences. We suggest that these three species should be transferred to Lecaimmeria , based on the following factors. Their morphology is consistent with Lecaimmeria according to molecular results and comparisons with type specimens, high-resolution photographs of the type materials and the original descriptions. One unknown " Immersaria " species from Macedonia is sister to Lecaimmeria iranica in the phylogenetic tree (Fig. 3 ), but comparison with high-resolution photograph and previous records ( Malíček and Mayrhofer 2017) show that it differs in its black margin of areolae and absence of gyrophoric acid. This unknown species with lecanorine apothecia is possibly a member of Lecaimmeria , but descriptions are lacking and the specimens were not seen. Thus, this species is temporarily retained in Immersaria .

Figures

Figure 3. Phylogenetic tree constructed from Maximum Likelihood analyses in Lecaimmeria, based on the concatenated nrITS-nrLSU-RPB 1 - RPB 2 dataset. Maximum Likelihood bootstrap probabilities above 70 % (left) and Bayesian Inference posterior probabilities above 0.9 (right) are given at the nodes. Solid purple rectangle: areolae margin white; solid grey rectangle: areolae margin black; hollow purple rectangle: areolae margin jade green pigmented. Solid blue circle gyrophoric acid; hollow blue circle: none.

Figure 7. Lecaimmeria botryoides (a-d KUN 20 - 66730): a-b thallus c apothecial anatomy. L. lyagea (e-h KUN 20 - 69070): e-f thallus g apothecial anatomy h scospores. Scale bars: 1 mm (a-b, e-f); 20 μm (c, g); 10 μm (d, h).

Figure 8. Lecaimmeria mongolica (a-d SDNU 20190354): a-b thallus c apothecial anatomy d ascospores. Scale bars: 1 mm (a-b); 20 μm (c); 10 μm (d).

Figure 9. Lecaimmeria orbicularis (a-e KUN 20 - 66753): a-b thallus c apothecial anatomy d ascus (Lugol's iodine) e ascospores. L. qinghaiensis (f-i KUN 20 - 68696): f-g thallus h apothecial anatomy i ascus. Scale bars: 1 mm (a-b, f-g); 20 μm (c, h); 10 μm (d, e, i).

Figure 10. Lecaimmeria tibetica (a-e KUN XY 19 - 1288): a-b thallus c apothecial anatomy d ascus e ascospore. L. tuberculosa (f-i KUN 18 - 58864): f thallus g conidiomata h apothecial anatomy i ascospores. Scale bars: 1 mm (a-b, f-g); 20 μm (c); 50 μm (h); 10 μm (d, e, i).