Carbacanthographis crassibasalia Shu H. Jiang & Z.F. Jia, 2024

Jiang, Shu-Hao, Hao, Cheng-Yue, Zhao, Xin & Jia, Ze-Feng, 2024, New species and record in the genus Carbacanthographis (lichenized Ascomycota, Graphidaceae) from China, Phytotaxa 670 (4), pp. 285-292 : 286-287

Carbacanthographis crassibasalia Shu H. Jiang & Z.F. Jia , sp. nov. Fig. 1

Differing from Carbacanthographis muriformis in the shorter and broader ascospores.

Mycobank No.: MB 853711

Type:— China. Guangxi Province: Nanning City, Mt. Damingshan , Natural Medicine Bath Valley . 1240 m elev., 108°26′18″E, 23°29′44″N, on the bark of Cinnamomum appelianum Schewe , 21 May 2015, Z. F. Jia GX 15362 ( LCUF – holotype; HMAS-L 140054 – isotype) .

Description: —Thallus crustose, corticolous, weakly corticate, pale gray to dark gray, epiperidermal, continuous, smooth, slightly glossy, tightly attached to the substratum; lacking isidia and soredia; prothallus absent. Ascomata lirellate, sessile, straight or sinuous, scattered, short, unbranched to sparsely branched, not striate, 1.8–3 mm long, 0.4–0.7 mm wide, terminally rounded. Thalline margin distinct, completely covering the proper excipulum, with indistinct patches of calcium oxalate crystals. Labia well developed, entire. Disc concealed, with slit-like appearance. Proper excipulum not striate, convergent, completely carbonized, 115–145 μm thick laterally, 330–350 μm thick at the base. Hymenium hyaline, not inspersed, 190–210 μm high, I–. Hypothecium hyaline, 40–45 μm high. Paraphyses parallel, simple or branched, septate, 2.5–3.5 μm wide, smooth at the tips. Periphysoids develop from the lateral proper excipulum, 6–7 μm wide, distinctly warty at the tips. Asci clavate, 1–2-spored, (85–) 120–155 × (10–) 20.5–40 μm. Ascospores hyaline, long ellipsoidal, muriform, 16–18 × 3–4-septate, (85–) 107–117 (–133) × (20–) 26–33 μm, I–, occasionally surrounded by a gelatinous layer of 8–17 μm thick. Pycnidia not observed.

Chemistry and spot tests: —Thallus K–, C–, P+ orange-red, UV–. TLC: protocetraric acid.

Etymology: —Named after the basally well developed proper excipulum.

Distribution and habitat: —Known only from the type locality, Mt. Damingshan, a national nature reserve in Guangxi, China. The new species grows on the bark of Cinnamomum appelianum Schewe at medium altitudes.

Notes: — Carbacanthographis crassibasalia can be recognized by its corticate thallus, sessile lirellae with complete thalline margin, entire labia, completely carbonized excipulum, warty periphysoid tips, hyaline hymenium, muriform, 6–18 × 3–4-septate ascospores [(85–) 107–117 (–133) × (20–) 26–33 μm] and the presence of protocetraric acid. It is similar to the North American species C. muriformis E. Tripp & Lendemer ( Tripp et al. 2010: 65) in the corticate thallus, the sessile lirellae with complete thalline margin, the completely carbonized excipulum, warty periphysoid tips, a hyaline hymenium and muriform ascospores and the presence of protocetraric acid, but differs in having 1–2 ascospores per ascus (vs. 4 ascospores per ascus), shorter and broader ascospores [about 4 times as long as wide vs. about 10 times as long as wide], and fewer transverse septations (16–18-septate vs. 25–37-septate). The new species is also similar to C. nitida Aptroot & M. Cáceres ( Sipman & Aptroot 2023: 332), described taxon from Brazil, in the corticate thallus, the completely carbonized excipulum, the I– ascospores, and the presence of protocetraric acid, but differs in the sessile (vs. erumpent) lirellae, fewer ascospores per ascus (1–2-spored vs. 8-spored) and the muriform (vs. transversely septate) ascospores. Another similar taxon is C. megalospora Feuerstein & R. M. Silveira ( Feuerstein et al. 2022: 57), a recently described taxon growing epiphytically in the Atlantic forest also in Brazil, which shares the corticate thallus, the completely carbonized excipulum and the muriform, I− ascospores, but differs in the much larger ascospores [(185–) 235–255 × 30–40 μm vs. (85–) 107–117 (–133) × (20–) 26–33 μm] and the presence of stictic, cryptostictic and constictic acids (vs. protocetraric acid).

This new species would be placed in the world key of Carbacanthographis by Feuerstein et al. (2022) in group key 3 at couplet 4 as: Ascospores 1–2-per ascus, (85–) 107–117 (–133) × (20–) 26–33 μm; protocetraric acid.

FIGTURE 1. Carbacanthographis crassibasalia (LCUF GX15362); A, B. Thallus with sessile, completely carbonized lirellae (scale = 0.2 mm). C. Apothecia section and warty periphysoids (scale = 100 μm). D. Apothecia section (in polarized light) showing with indistinct patches of calcium oxalate crystals (scale = 100 μm). E–I. Asci (scale = 50 μm). J. Paraphyses (scale = 50 μm). K–M. Ascospore, occasionally surrounded by a gelatinous layer (scale = 50 μm).