Helvella pseudoatra Q. Zhao, 2023

Bao, Shu-Xin, Li, Ying, Zhou, De-Qun, Thongklang, Naritsada, Yu, Feng-Ming & Zhao, Qi, 2023, Two new species of the fallax-pezizoides complex in Helvella (Helvellaceae, Pezizales) from Yunnan, China, Phytotaxa 626 (4), pp. 279-289 : 284-285

Helvella pseudoatra Q. Zhao , sp. nov. ( Fig. 4 )

Index Fungorum number: IF 552243, Facesoffungi number: FOF 03268

Etymology: The specific epithet pseudoatra refers to the morphological similarity of the new species to Helvella atra .

Type: China, Yunnan Province, Gongshan County, on the ground, under a forest dominated by Quercus , alt. 1900 m, 29 July 2011, Q. Zhao 1070 ( HKAS 74023 , holotype).

Diagnosis: Similar to Helvella atra but differs in their stipe.

Pileus saddle-shaped to slightly irregularly lobed, 1–2.5 cm high, 1–2.5 cm broad, margin merged each other in several places and fused with stipe, hymenium even, brown, dark brown to black when fresh, becoming blackish when dried, receptacle surface pubescent, dark grey to greyish black when fresh, becoming blackish when dried. Stipe 1.3–5 cm long, 0.2–0.5 cm broad, terete, finely pubescent, upward white to brownish, base part white to greyish when fresh, becoming brownish when dried.

Medullary excipulum 120–260 µm broad, of textura intricata, hyaline, composed of 2.5–4 µm broad hyphae, walls thickened, J-. Ectal excipulum 40–85 µm broad, of textura angularis, hyaline, terminal cells 15–30 × 8–13 μm, blue in cotton blue, J +. Stipitipellis 90–240 µm, of textura angularis, hyaline, terminal cells 12–30 × 8–18 μm, blue in cotton blue, J +. Asci arising from croziers, 8-spored, subcylindrical to clavate, with apex rounded, 190–235 × 15–20 µm, J- in Melzer’s reagent, blue in cotton blue. Paraphyses filiform, 3–4 µm broad, slightly exceeding the asci, apex enlarged, 4–5 µm broad, hyaline, blue in cotton blue, J-. Ascospores [80/2/2, in H 2 O] 15–19 (–20) × (10.5–) 11–14 μm [Q = 1.26–1.63, Q = 1.39 ± 0.08)], broadly ellipsoid to ellipsoid, smooth-walled under the light microscope.

Habitat and known distribution: Scattered or gregarious on the ground, associated with Quercus . Currently only known in southwest China.

Other material examined: China, Yunnan Province, Yulong County, on the ground, under a Quercus forest, alt. 2000 m, 20 July 2008, Q. Zhao 8296 (HKAS 54996).

Notes: Morphologically, Helvella pseudoatra resembles H. atra , and H. liquii ( Skrede et al. 2017) . However, the receptacle surface of H. atra is glabrous, and that of H. pseudoatra is pubescent. Additionally, H. atra is blackish with a dark violet brown tinge stipe ( Skrede et al. 2017). In contrast, H. liquii exhibits a dark brown to blackish stipe when fresh, while the base part of H. pseudoatra appears white to greyish.

Phylogenetically, H. pseudoatra forms a sister group with H. liquii in the fallax-pezizoides lineage ( Fig. 1 ). The pairwise homoplasy index (PHI) value of 1.0, indicates no significant genetic recombination between them and confirms that they are different species ( Fig. 2 ).

Figures

FIGURE 1. The phylogenetic tree obtained by RAxML analysis of combined LSU and hsp90 sequence data. Four taxa (H. rivularis H276, H365; H. paraphysitorquata H271, MA Fungi: 24512) were used as outgroup. The node shows the bootstrap support value with ML greater than or equal to 75% and the BI posterior probability greater than or equal to 0.9. The new isolates of this study are in red. Sequences from holo-, iso-, epi- and neotype specimens are in bold.

FIGURE 2. The results of the pairwise homoplasy index (PHI) test for closely related species of Helvella liquii with H. pseudoatra using LogDet transformation. PHI test results (Φw) <0.05 indicate significant recombination within the dataset.

FIGURE 4. Helvella pseudoatra (HKAS 74023, holotype). A−B. Typical mature specimens (A: HKAS 74023. B: HKAS 54996). C−D. Receptacle surface of pileus. E. Stipitipellis. F. Asci and paraphyses. G−L. Asci. M. Ascospores. Scale bars: A−B = 1 cm. C−E = 50 μm. F−M = 20 μm.