Scleroderma longistipes Gonkhom, Sysouph. & Thongkl., 2025

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 longistipes Gonkhom, Sysouph. & Thongkl. sp. nov.

Fig. 2

Diagnosis.

Epigeous brown to burnt umber basidiomata with long stipe, rubbery pale brown peridium, hyaline to yellow brown hyphae in exoperidium, hyaline hyphae in endoperidium, globose dark brown basidiospores with echinulate or spinose ornamentation.

Holotype.

Thailand • Chiang Rai Province, Mueang Chiang Rai District, Mae Fah Luang University campus , 04 June 2019, collected by Didsanutda Gonkhom, DG 109 ( MFLU 19-1655 ).

Etymology.

The species name ( longistipes) refers to the long stipe of the basidiomata.

Description.

Basidiomata epigeous, 28–35 mm in diam., 42–60 mm high, club-shaped, with globular peridial head; with cracked to squamulose surface, brown (6 E 5) background when young, with fawn (7 E 4) to brown (6 E 5) or burnt umber (6 F 6) squamular cracks upon luteous background, hard skin, tough when mature. Stipe sub-cylindric, fat, with small irregular cracks at the top of the strip, 35–45 × 10–13 mm, white background, covered with brown (6 E 5) fibrillose squamules. Rhizomorphs more aggregated at the base, white, branched, and narrowing towards the base. Context white in peridium and stipe, turned dull red to greyish red (98 B 4-5) when cut. Peridium up to 5 mm wide when fresh, rubbery in consistence, pale brown (6 D 5).

Peridium layer formed by simple-septate hyphae. Exoperdium slightly thickened walls, composed of interwoven to ramified and superimposed hyphae, hyaline to yellow brown, 2.9–3.8 µm diam. Endoperdium thick, composed of interwoven hyphae, hyaline, 4.3–7.2 µm diam. Clamp connections present on endoperidium hyphae. Gleba brownish grey (9 E 2), greyish brown (9 E 3), or oxblood red (9 E 7) to dark brown (9 F 4-7), compact, and powdery when mature. Basidiospores (n = 50) globose, echinulate, dark brown in KOH, (13.4 –) 14.5–17.2 (19.5) µm in diam., with brown spinose ornamentation (2.6–5.9 µm high). Basidia not seen.

Habitat and distribution.

Caespitose or fasciculated on soil, epigeous, in northern Thailand.

Additional specimens examined.

Thailand • Chiang Rai Province, Mueang Chiang Rai District, Mae Fah Luang University campus , 04 June 2019, collected by Didsanutda Gonkhom, DG 110 ( MFLU 19-1656 ) .

Notes.

Scleroderma longistipes is characterized by a larger brown basidiomata with a longer stipe that turns from dull red to greyish red when touched. The basidiospores are globose with longer brown spines. According to the phylogenetic analysis (Fig. 1 ), Thai specimens of Scleroderma longistipes are identical to an unknown species from Malaysia (LH 35) ( Peay et al. 2010) and an unknown species from Thailand (ECM 26 - SERS) ( Yuwa-Amornpitak et al. 2006). However, these two taxa were only identified as Sclerodermataceae species. Scleroderma separatum Z. W. Ge, R. Wu & L. R. Zhou , a species originally described from Yunnan, southwestern China, is a species related to S. longistipes by having a stipe. However, Scleroderma longistipes appears closely related to S. separatum , has smaller basidiomata, a greenish yellow background, a slender stipe (5–30 × 3–5 mm), smaller basidiospores (4.5–8.5 µm), and shorter basidiospore spines (1.2–2.5 µm) ( Wu et al. 2023). Furthermore, S. separatum is related to S. longistipes by phylogenetic analysis with low bootstrap support ( BS) (Fig. 1 ).

Scleroderma longistipes is also similar to S. columnare Berk. & Broome. However , S. columnare has stellate dehiscence at the upper part of basidiomata in old specimens ( London 1911), and S. columnare is also related to S. longistipes with low BS (Fig. 1 ). Additionally, S. nitidum Berk. is morphologically similar to S. longistipes , sharing the stipitate morphology but differing in having a glossy peridium, smaller basidiospores (5–7 µm) with denser, shorter spines, and no color change when bruised ( Guzmán 1970).

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 2. Scleroderma longistipes (MFLU 19-1655, holotype). A, B. Basidiomata; C. Scale on peridium surface; D. Cut side of peridium of MFLU 19-1655; E, F. Basidiomata; G. Scale on peridium surface; H. Cut side of peridium of Scleroderma longistipes (MFLU 19-1656); I. Exoperidial hyphae; J. Endoperidial hyphae; K. Clamped hyphae of endoperidium; L – Q. Basidiospore. Scale bars: 10 mm (A, B, E, F); 5 mm (C, D, G, H); 50 µm (I, J); 20 µm (K); 10 µm (L – Q).