Herpothallon lilacinum L.L. Liu & Lu L. Zhang, 2023

Liu, Linlin, Zuo, Qijia, Xue, Junxia, Ren, Zhaojie & Zhang, Lulu, 2023, Three new species of Herpothallon (Lichenized Ascomycota) from Southern China, Phytotaxa 597 (4), pp. 287-296 : 291-293

Herpothallon lilacinum L.L. Liu & Lu L. Zhang , sp. nov. Mycobank number: 845790 ( Figs 3 , 4 )

Type:— CHINA. Guizhou Province: Tongren City, Yang Jia Ao township , Bi Er Tang village . 874 m elev., 27°52’27.59” N, 107°58’10.71” E, on rock, 10 June 2022, L.L. Liu, Y.X. Bi, Z.H. Jiang & D.C. Yan 20220232 (Holotype in SDNU) .

Thallus corticolous or saxicolous, up to 3.5 cm across, irregular shaped, sometimes flaking off, loosely appressed to the substrate, rather soft, felty, often seemingly farinose, dull, white to cream white, in section up to 200 µm thick, with many calcium oxalate crystals throughout the thallus (insoluble in KOH, dissolving and recrystallizing as colourless, needle-shaped crystals in 10% H 2 SO 4), with 1–2 µm wide hyphae. Hypothallus whitish, byssoid, composed of 1–2 µm wide hyphae. Prothallus up to 0.8 mm broad, whitish, indistinct, byssoid to cottony, composed of interwoven and radiating hyphae. Pseudisidia numerous, unbranched, soft, whitish subglobose or irregularly cushion-shaped, fluffy-felty with many projecting hyphae, basally of the same colour as the thallus, upper parts often lilac to lilac grey, 0.1–0.45 mm in diam.. Photobiont trentepohlioid, in short, irregular threads; cells yellowish green, 10–15 × 5–8 μm. Asci and pycnidia not seen.

Chemistry and spot tests: Thallus and prothallus K−, C−, P+ bright yellow, UV−, I+ blue in medulla, the lilac to lilac grey parts K+ black blue, C−. TLC: psoromic acid (major), an unknown substance (minor), 2’-O-demethylpsoromic acid (minor).

Etymology: The epithet “ lilacinum ” refers to the lilac to lilac grey pseudisidia.

Ecology and distribution: The new species was found growing on rock wall by the roadside and bark of a tree in Guizhou Province.

Notes: This species is characterized by the subglobose or irregularly cushion-shaped, lilac to lilac grey, fluffy-felty pseudisidia, 0.1–0.45 mm in diam., the psoromic and 2’-O-demethylpsoromic acids, and an unknown substance chemistry. Herpothallon lilacinum is most similar to H. weii Yuliang Chen & Haiying Wang (2012: 440) : both contain psoromic acid and the similar unknown substance, but H. weii has a tightly appressed thallus, an I− medulla, a distinct prothallus, pinkish and larger, and not whitish subglobose pseudisidia, up to 1 × 0.5 mm ( Cheng et al. 2012). Crypthonia albida (Fée) Frisch & G. Thor (2010: 290) also has fluffy-felty pseudisidia and contains psoromic acid as its major substance, but has loosely byssoid, whitish pseudisidia, up to 1.0 × 1.0 mm (Frisch & G. Thor, 2010). Herpothallon himalayanum Jagadeesh & Sinha (2009: 40) and H. capilliferum Pengfei Chen & Lulu Zhang (2022: 02) are also similar to H. lilacinum in producing fluffy-felty pseudisidia, but they differ in secondary chemistry: Herpothallon himalayanum contains gyrophoric acid as its major substance (Jagadeesh & Sinha, 2009), and H. capilliferum only contains norstictic acid ( Chen et al. 2022).

Phylogenetically, H. lilacinum clusters with H. echinatum and H. glaucescens ( Fig. 1 ), they all possess psoromic acid as major, but H. echinatum and H. glaucescens have subglobose or cylindrical pseudisidia, all without the unknown substance.

Additional specimen examined: CHINA. Guizhou Province: Tongren City, Yang Jia Ao township, Bi Er Tang village . 874 m elev., 27°52’27.59” N, 107°58’10.71” E, on rock, 10 June 2022, L.L. Liu, Y.X. Bi, Z.H. Jiang & D.C. Yan 20220231, 20220237, 20220238, 20220239, 20220240, 20220253 ( SDNU) ; Guizhou Province: Tongren City, Xu Jia Ba town, Zhang Jia Gou village , along the stream. 851 m elev., 27°55’33.38” N, 108°1’59.13” E, on bark of a tree, 11 June 2022, L.L. Liu, Y.X. Bi, Z.H. Jiang & D.C. Yan 20220090 ( SDNU) .

Figures

FIGURE 1. Phylogenetic tree constructed from Maximum Likelihood analysis of Herpothallon species, based on the mtSSU dataset. Maximum likelihood (ML) bootstrap value ≥ 70, and Bayesian posterior probabilities (PP) value ≥ 0.95 are shown above the branches. Bootstrap values are shown in the order of ML, PP in the tree. Newly described species are marked in bold. Scale = 0.02 substitution per site.

FIGURE 3. A–B. Herpothallon lilacinum growing on rock, (holotype, SDNU 20220232). A. Thallus and prothallus. Scale = 1 mm.. B. Pseudisidia. Scale = 400 µm. C–D. The new species H. lilacinum growing on bark, (paratype, SDNU 20220090). C. Thallus. Scale = 1.5 mm. D. Pseudisidia. Scale = 600 µm.

FIGURE 4. TLC of H. lilacinum with C system (at: atranorin; U: the unknown substance; P: psoromic acid).