Moniliophthora sclerotium L. P. Tang, W. H. Zhang & G. L. Zhang, 2025

Moniliophthora sclerotium L. P. Tang, W. H. Zhang & G. L. Zhang sp. nov.

Fig. 7 A – C, F Chinese name: 菌核丛梗霉皮伞 View Figure 7

Diagnosis.

Sclerotia relatively small, 0.5–2.5 cm diam., globose to irregularly shaped; outer layer thin, grey-brown to grey-black (2 D 2–2 F 2) when fresh, turning dark grey (2 F 2) when dried. Composed of compact filamentous and vascular hyphae, 1.5–8 μm wide, thin-walled, hyaline. Sclerotial rind yellowish-brown to dark brown pigmentation in KOH.

Etymology.

“ sclerotium ” denotes the dense, compact resting structure typical of certain fungi, emphasising its key features.

Holotype.

China: • Yunnan Province: 10 August 2020, MHKMU P 28 , GenBank Acc. No.: ITS = PV 862918 , nrLSU = PV 862940 .

Description.

Sclerotia globose, elliptical to irregularly shaped, 0.5–2.5 cm diam.; peridium thin, grey-brown to grey-black when fresh, turning dark grey with irregular block-like cracks when dried; internal structure compact and hard, often exhibiting white marble-like veins. Odour indistinct. Sclerotial context primarily composed of compact, abundant thin-walled, hyaline hyphae, plus viscous substances; filamentous hyphae 1.5–4 μm wide, vascular hyphae 5–8 μm wide. Clamp connections present, rare. Sclerotial rind yellowish-brown to dark brown pigmentation in KOH.

Habit and habitat.

Scattered to gregarious on decayed wood.

Distribution.

Currently known only from Yunnan Province.

Additional materials examined.

China: • Yunnan Province: 10 August 2020, MHKMU L 1-1 .

Notes.

According to Index Fungorum ( http://www.indexfungorum.org, accessed 24 June 2025), the genus Moniliophthora currently comprises 14 accepted species. Amongst these, M. sclerotium is the first and only species reported to form sclerotia, representing a significant expansion of the known ecological and morphological diversity within this genus.

Similar to the sclerotia of Gerronema species, those of M. sclerotium are also used in traditional Chinese medicine under the name of “ Leiwan ”. To date, basidiomata of M. sclerotium have not been observed; thus, only its sclerotia are described here. Although the sclerotia of M. sclerotium , G. brunneosquamulosum and G. sinense all share a compact internal structure — often exhibiting a marbled pattern in cross-section — they can be reliably distinguished by several morphological features.

Macroscopically, the sclerotia of M. sclerotium are comparatively small ( 0.5–2.5 cm in diameter) and possess a dark outer rind, ranging from grey-brown to grey-black. In contrast, G. brunneosquamulosum produces dark brown sclerotia, whereas these of G. sinense are distinctly reddish-brown, especially in fresh specimens.

Microscopically, the sclerotia of M. sclerotium are characterised by the presence of abundant vascular hyphae, a diagnostic feature not observed in either Gerronema species. Furthermore, the sclerotia of G. brunneosquamulosum are composed predominantly of dense, thick-walled hyphae, whereas those of G. sinense consist mainly of compact filamentous hyphae with less associated viscous material.

By comparison, L. mylittae , a species historically suggested as a source of Leiwan ( Dai and Yang 2008), differs markedly in sclerotial morphology. Its sclerotia can reach up to 20 cm in diameter and display a distinctive honeycomb-like internal architecture ( Robinson 2007), which is inconsistent with the features of authentic Leiwan material derived from the taxa described above.