Gerronema sinense L. P. Tang, W. H. Zhang & G. L. Zhang, 2025

Zhang, Wen-Hao, Zhang, Guo-Li, Lei, Han-Chi, Xu, Chang, Li, Jia, Xia, Xing, Jiang, Shuai, Li, Na & Tang, Li-Ping, 2025, Multi-origin analysis of the traditional Chinese medicine Leiwan, MycoKeys 125, pp. 325-345 : 325-345

Gerronema sinense L. P. Tang, W. H. Zhang & G. L. Zhang sp. nov.

Figs 4 , 6 , 7 E Chinese name: 中华老伞

Diagnosis.

Distinguished from other Gerronema species by its funnel-shaped pileus with a yellow-brown surface that becomes dark brown at the centre when mature and a pale grey-brown margin with radial striations or small scales. It is also characterised by a slender and hollow stipe covered with grey squamules, ellipsoid to elongate-ellipsoid basidiospores and the presence of clamp connections. Sclerotium primarily composed of compact filamentous hyphae and viscous substances.

Etymology.

“ Sinense ” refers to “ Chinese ”.

Holotype.

China: • Hainan Province: Ledong Li Autonomous County (乐东黎族自治县), Jianfengling (尖峰岭), Mingfeng Valley (鸣凤谷), 18°44'16"N, 108°50'11"E, elev. 810 m, 10 August 2020, Man Mu ( MHKMU MM-642 ), GenBank Acc. No.: ITS = PV 862917 , nrLSU = PV 862938 .

Description.

Basidiomata small and flexible. Pileus approximately 3.5 cm diam., dry, centrally depressed, umbilicate; surface with prominent radial striations, yellow-brown (2 B 8–2 B 6) to darker brown (2 D 6–2 E 6) at centre, grey-brown (2 C 4–2 C 2) at margin. Context thin, white (1 A 1). Lamellae decurrent, creamy-white (1 A 1), about 40 pieces of complete lamellae per pileus. Stipe ca. 6.0 × 0.5 cm, central, cylindrical, hollow; surface densely covered with grey (1 B 1) scales near the apex, less evident towards the base, which is swollen and paler. Odour and taste indistinct. The cultured mycelium of G. sinense displays slower radial expansion. Colonies are characterised by a dense, floccose to tomentose aerial mycelium that is markedly elevated above the agar surface. The colony edge is irregular and poorly defined.

Basidiospores [40 / 1 / 1] (6.5) 7.0–8.5 (9.0) × 4.0–5.0 (6.0) μm [Q = 1.4–1.77 (2.0), Q m = 1.58 ± 0.15], inamyloid, ellipsoid to elongate-ellipsoid. Basidia 25–35 × 6–8 μm, 4 - spored, clavate; sterigmata up to 5 μm long. Cheilocystidia 18–30 × 2–6 μm, narrowly clavate or subfusiform, thin-walled. Pleurocystidia absent. Lamellar trama subregular; hyphae 2–12.5 μm wide, thin-walled, hyaline. Pileipellis a cutis; hyphae 1.5–8 μm wide, light yellow to yellow (1 A 6–1 B 6), occasionally with coarse excrescences; terminal elements 20–120 × 4–12.5 μm, clavate, sometimes with sparse coarse excrescences, light yellowish-brown to yellowish-brown (2 B 5–2 C 5) pigment in KOH. Pileus trama subregular, sarcodimitic, sometimes with yellowish-brown (2 B 4) to dark brown (2 D 4) hyphae. Stipitipellis composed of hyphae, 2–8 μm wide, hyaline, smooth. Caulocystidia 20–95 × 4–12 μm, cylindrical or clavate, thin-walled; light yellowish-brown (2 A 7–2 A 5) pigment in KOH. Clamp connections present in all tissues.

Sclerotia 1.8–3.5 cm diam., elliptical to irregularly shaped; peridium thin, surface reddish-brown (7 C 7–7 C 8) with irregular block-like cracks and fissured when fresh, drying dark purplish-red (11 C 8–11 D 8) with deep cracks and slightly wrinkled texture. Internal structure compact and hard, often exhibiting white marble-like veins. Odour indistinct. Rhizomorphs reddish-brown (7 C 7), arising from sclerotia, caducous upon drying. Sclerotial context primarily composed of compact filamentous hyphae with viscous substances, 1–5 μm wide, thin-walled, hyaline. Clamp connections present, rare. Sclerotial rind with yellowish-brown (2 B 5–2 D 5) pigment in KOH.

Habit and habitat.

Scattered to gregarious on decayed wood. Found in broadleaf forests dominated by Cyclobalanopsis blakei (Skan) Schottky , Lithocarpus amygdalifolium (Skan) Hayata and Castanopsis carlesii (Hemsl.) Hayata ( Fagaceae ).

Distribution.

Currently known from south and southwest China: Chongqing, Hainan, Sichuan and Yunnan.

Additional materials examined.

China: • Chongqing Province: Wushan County (巫山县), elev. 800–1200 m, 10 August 2019, CQWS ; • Yunyang County (云阳县), elev. 400–600 m, 10 August 2018, CQYY . • Sichuan Province: Wanyuan City (万源市), elev. about 900–1200 m, 27 October 2019, SCWY , • Yunnan Province: Puer City (普洱市), Simao District (思茅区), elev. about 1300 m, 18 September 2020, Li-Ping Tang ( MHKMU TLP-3502 ) .

Notes.

The genus Gerronema currently comprises more than eighty species names according to Index Fungorum ( http://www.indexfungorum.org, accessed 24 June 2025). Amongst them, only two species, G. brunneosquamulosum and G. sinense , are known to form sclerotia, which are collectively utilised in traditional Chinese medicine as “ Leiwan ”. In the phylogenetic tree (Fig. 1 ), G. sinense does not form a well-supported clade with any currently recognised taxa, including G. brunneosquamulosum , which supports its status as a distinct species.

Morphologically, G. brunneosquamulosum is distinguished by its relatively large basidiomata with the pileus reaching up to 6 cm in diameter. The pileus surface exhibits prominent radial striations at juvenile stages, which become less distinct at maturity. The context is thin and the pileus margin is slightly involute. The stipe is either glabrous or bears sparsely distributed squamules.

Conversely, G. sinense produces smaller basidiomata, but retains conspicuous, persistent radial striations throughout its development. The stipe is distinctly adorned with densely aggregated squamules, particularly concentrated in the subapical region. In culture, G. brunneosquamulosum exhibits prostrate, radiating mycelia that form concentric rings with smooth margins, whereas G. sinense grows more slowly, producing dense, floccose aerial mycelia with irregular colony margins.

A detailed comparison of sclerotial characteristics between these two species and M. sclerotium is provided in the notes for the latter.

Figures

Figure 1. Phylogenetic tree of Gerronema inferred, based on ITS-nrLSU dataset. RAxML bootstrap values (MLB ≥ 50 %) and Bayesian posterior probabilities (BPP ≥ 0.90) are indicated above the branches. Newly-generated sequences are highlighted in red.

Figure 4. Fresh basidiomata and sclerotium of Gerronema sinense. A, B. Basidiomata; C, D. Sclerotium (A, B from MHKMU MM- 642, holotype; C, D from MHKMU TLP- 3502). Scale bars: 1 cm (A – D).

Figure 6. Microscopic features of Gerronema sinense (MHKMU MM- 642, holotype). A. Basidiospores; B. Basidia; C. cheilocystidia; D. Pileipellis; E. Sclerotium hyphae; F. Stipitipellis and caulocystidia. All structures were mounted in 5 % KOH. A – C were stained with 1 % Congo Red. Scale bars: 10 μm (A – C); 20 μm (D – F).

Figure 7. A – C Sclerotium and microscopic features of Moniliophthora sclerotium (MHKMU P 28, holotype). D – F. Sclerotial rind (D. Gerronema brunneosquamulosum; E. Gerronema sinense; F. Moniliophthora sclerotium). Structures in B – F were mounted in 5 % KOH. Scale bars: 1 cm (A); 25 μm (B, C); 50 μm (D – F).