Helvella guttata Q. Zhao & J. R. Lu 2023, sp. nov

Helvella guttata Q. Zhao & J.R. Lu sp. nov Fig. 1, 2 Index Fungorum number: IF 900384; Faces of Fungi number: FoF 14372. Etymology: Guttata refers to its guttata hymenium surface. Holotype: CHINA, Yunnan Province, Lushui County, Luzhuang, alt. 900 m, 26 Aug. 2009, Qing Cai 274 (HKAS 67836). Diagnosis: Similar to Helvella macropus but differs in its constantly mottled hymenium, and larger subellipsoid to subfusiform ascospores. Sexual morph: Pileus shallowly cupulate to discoid, 0.3–1 cm high, 1–2.5 cm broad, hymenium even, brown to dark brown, constantly mottled with patches of paler pigmentation when fresh, brownish when dried, receptacle surface villose to densely pubescent, greyish, light brown to dark brown when fresh, becoming greyish brown to dark brown when dried. Stipe 1–6 cm long, 0.2–0.5 cm diam, terete, internally solid, villose to densely pubescent, concolorous with the receptacle surface. Medullary excipulum 200–350 μm broad, of textura intricata, hyaline, composed of 3–7 μm diam hyphae, walls thickened, J-. Ectal excipulum 90–180 μm broad, of textura angularis, brown, terminal cells 18–40 × 7–13 μm, blue in cotton blue, J-. Stipitipellis 140–250 μm, of textura angularis, hyaline, terminal cells 18–28 × 7–15 μm, blue in cotton blue, J-. Asci arising from croziers, 8-spored, subcylindrical to clavate, with apex rounded, 200–300 × 14–22 μm, J- in Melzer’s reagent, blue in cotton blue. Paraphyses filiform, 3–4 μm dia., slightly exceeding the asci, apex enlarged, 7–10 μm dia., brown, blue in cotton blue, J-. Ascospores [80/4/2, in H 2 O] (20–)21–27.5(–28) × (11–)11.5–15(–16) μm [Q = 1.56–2.16, Q m = 1.78 ± 0.18)], subellipsoid to subfusoid, smooth-walled under the light microscope, uniguttulate, with large central globose to broadly ellipsoidal oil droplet. Asexual morph: Undetermined. Habitat: Scattered or gregarious on the ground, under Quercus spp. forest. Distribution: Currently only known in southwestern China. Material examined: CHINA, Yunnan Province, Lushui County, under Quercus sp. forest, alt. 1000 m, 26 Aug. 2009, Ting Guo 56 (HKAS 69046), same location, 6 Aug. 2010, Ting Guo 150 (HKAS 69546); Lijiang City, under Quercus sp. forest, alt. 2600 m, 20 Aug. 2010, Qi Zhao 1012 (HKAS 69733); Tibet, Bomi County, under Quercus sp. forest, alt. 2700 m, 30 Jun. 2014, Qi Zhao 2079 (HKAS 87759). Notes: Morphologically, H. guttata and H. macropus both share cupulate pileus, villose receptacle, and stipe surface, and subfusiform ascospores. However, the latter species never possess mottled apothecia, and the hymenium or receptacle surface is usually light to medium brown or greyish brown. In microstructure, H. macropus has slenderer ascospores than H. guttata. In phylogeny, H. guttata is the sister of H. macropus, which has relatively high statistical support (Fig. 1). The comparison of H. guttata with its phylogenetic relatives (H. ephippioides, H. fibrosa, and H. macropus) in fibrosa–macropus lineage is shown in Table 2.
Published as part of Lu, Jin-Rong, Yu, Feng-Ming, Lei, Lei, Zhang, Ying & Zhao, Qi, 2023, A new species of Helvella (Helvellaceae, Pezizomycetes) within the H. macropus group from China, pp. 212-222 in Phytotaxa 601 (3) on pages 216-217, DOI: 10.11646/phytotaxa.601.3.2, http://zenodo.org/record/8141752