Scleroderma separatum Z. W. Ge, R. Wu & L. R. Zhou.

Gonkhom, Didsanutda, Sysouphanthong, Phongeun, Stadler, Marc, Thongklang, Naritsada & Hyde, Kevin D., 2025, Three new species and one new record of Scleroderma (Sclerodermataceae, Boletales) from northern Thailand, MycoKeys 123, pp. 69-88 : 69-88

Scleroderma separatum Z. W. Ge, R. Wu & L. R. Zhou.

Fig. 5

Description.

Basidiomata are epigeous, 12–28 mm in diam., 17–45 mm in height, globose, subglobose to irregularly oblate, tan (3 D 3) to ochraceous – brown (5 E 2). Peridium is leathery, thin, 0.5–1.0 mm thick when fresh, and becomes much thinner when dry, hay (5 C 4) to greenish-yellow (3 B 4) background. Peridium layer formed by hyphae simple-septate, with slightly thickened walls, interwoven, hyaline, exoperidium 2.4–4.4 µm in diam., and endoperidium 4.1–6.0 µm in diam. with clamp connections. Gleba grey (8 F 1) – dark brown (8 F 5), compact, and powdery when mature. Stipe is subcylindric, 20–50 mm in length and 5–10 mm in diam., with numerous white rhizomorphs at the base. Basidiospores globose, occasionally subglobose, dark brown in KOH, (12.31 –) 13.23–14.35 (– 16.49) × (11.53 –) 13.78–14.29 (– 16.30) µm in diam., including ornamentation (spinose up to 1.7–3.9 µm high), n = 50, coated by crowded curved spines. Basidia not seen.

Habitat and distribution.

Caespitose or fasciculated on soil, epigeous, in tropical and temperate regions of China and Thailand.

Specimens examined.

Thailand • Chiang Mai Province, Mae Rim District, Mae Sa , 28 July 2010, MFLU 19-1347 (NTF 066) .

Note.

This is based on a single Thai specimen. Thai specimens are considered to be similar to specimens of S. separatum from Southwestern China by having epigeous basidiomata. The molecular analysis also supports identification (Fig. 1 ). The species grows under a forest dominated by Pinus yunnanensis ( Wu et al. 2023) . Nonetheless, the samples from Thailand were frequently taken from mixed forests or the litter of Pinus trees. These results suggest that this species is found on both Quercus and Pinus . Since the initial description, this is the second record of the species.

Among 82 accessions, including the newly described species, the length of the entire ITS, LSU, rpb 2, and tef 1 - α comprised 4233 base pairs. The Scleroderma species known from this study include Scleroderma columnare , S. sinnamariense , and S. suthepense (Fig. 6 ).

Figures

Figure 1. Phylogenetic tree obtained from the maximum likelihood analysis of Scleroderma species. Maximum likelihood tree obtained from the alignment of ITS, LSU, rpb 2, and tef 1 - α sequences. The bootstrap consensus tree was inferred from 1000 replicates. Pisolithus aurantioscabrosus was included as an outgroup.

Figure 5. Scleroderma separatum (MFLU 19-1347). A. Basidiomata; B. Cut side of the peridium; C. Exoperidial hyphae; D. Endoperidial hyphae; E. Clamped hyphae of endoperidium; F – L. Basidiospore. Scale bars: 10 mm (A, B); 50 µm (C); 20 µm (D); 10 µm (E); 20 µm (F – L).

Figure 6. The mature basidiomata of Scleroderma spp. in this study. A, B. S. columnare; C – K. S. sinnamariense; L, M. S. suthepense. Scale bars: 10 mm.