Sistotremastrum massonianum L.X. Hou, X.L. Li, Meng Zhou, Yuan Yuan, 2025

Hou, Li-Xin, Li, Xiang-Lin, Luo, Kai-Yue, Dai, Yu-Cheng, Yuan, Yuan & Zhou, Meng, 2025, A new species of Sistotremastrum (Sistotremastrales, Basidiomycota) from subtropical China, Phytotaxa 690 (1), pp. 89-98 : 93-95

Sistotremastrum massonianum L.X. Hou, X.L. Li, Meng Zhou, Yuan Yuan sp. nov. ( Figs. 2 and 3 )

MycoBank No.—MB 855477

Etymology:— Massonianum (Lat.): refers to the species mostly growing on Pinus massoniana .

Holotype:— CHINA. Zhejiang Province, Jinhua, Wuyi County, Shiehu Scenic Spot , 28.91209° 119.7345°, on rotten wood of Pinus massoniana , 11 Aug. 2023, Dai 25537 ( BJFC 043086 ).

Description:—Basidioma annual, widely effused, adnate, inseparable from substrate, thin, subcoriaceous when fresh, crustaceous when dry, first as small patches, later confluent up to 14 cm long, 7 cm wide, 200 µm thick in section, soft and without odor or taste when fresh. Hymenophore grandinoid to odontoid, farinaceous, white when young, becoming cream to buff with age, finely cracked with age. Margin thinning out as byssoid, white, 2–3 mm wide. Aculei or spines loosely arranged, conical to cylindrical, 3–5 per mm, up to 1 mm long.

Hyphal system:—Monomitic; generative hyphae with clamp connections, IKI−, CB−, tissues unchanged in KOH.

Subiculum very thin to almost absent, white to cream. Subicular hyphae hyaline, thin-walled to occasionally slightly thick-walled, up to 0.4 μm in thickness, smooth, moderately branched and septate, loosely interwoven to subparallel, branched mostly at sharp angles, 2.3–4.7 μm in diam. Tramal hyphae, hyaline, thin- to slightly thick-walled, up to 0.3 μm in thickness, smooth, frequently branched, moderately septate, interwoven, 2–4.4 μm in diam. Subhymenial hyphae thinner, thin- to slightly thick-walled, smooth, frequently branched, moderately septate, interwoven, agglutinated and not easy to discern, 1.6–3.4 μm in diam.

Hymenium:—Hyphidia occasionally present, hyaline, thin-walled, smooth, embedded or slightly projecting beyond the hymenium, clamped at the base, up to 17.1 um long and 2 μm in diam. Basidia clavate to barrel-shaped, hyaline, thin-walled, smooth, with four sterigmata and a basal clamp connection, 8.5–12.1 × 3.5–4.8 μm; basidioles similar to basidia but slightly smaller.

Basidiospores:—Narrowly ellipsoid to broadly cylindrical, hyaline, thin-walled, smooth, IKI–, CB−, (2.8–)3.3– 4.8(–5.5) × (1.9–)2.1–2.8(–3.0) µm, L = 4.12 µm, W = 2.74 µm, Q = 1.58–1.72 (n = 150/5).

Type of rot:—White rot.

Additional specimens examined (paratypes):— CHINA. Guizhou Province, Guiyang, Qianlingshan Park, 26.5866° 106.697°, on fallen trunk of Pinus massoniana , 21 Aug. 2023, Dai 25792 (BJFC 043341); on rotten wood of P. massoniana, Dai 25773 (BJFC 043322), Dai 25787 (BJFC 043336). Zhejiang Province, Jinhua, Wuyi County, Shiehu Scenic Spot, on fallen trunk of Cunninghamia sp. , 11 Aug. 2023, Dai 25520 (BJFC 043068).

Notes:—Phylogenetically, S. aculeatum and S. aculeocrepitans are closely related to S. massonianum , but there are obvious morphological differences among them. S. aculeatum differs from S.massonianum by more loosely spines (2−3 per mm vs. 3−5 per mm) and spines that tend to fuse together and produce shallow, wide pores 0.5–1 per mm. Sistotremastrum aculeocrepitans is also different from S.massonianum by ceraceous and darkening mature parts, ochraceous to light orange of basidiomata and longer basidia (14−19 μm vs. 8.5−12.1 μm, Gruhn et al. 2018; Spirin et al. 2021).

Figures

FIGURE 2. Basidioma of Sistotremastrum massonianum (holotype, Dai 25537), A The front of the basidioma; B Characteristic hymenophore. Scale bars:A and B = 1 cm.

FIGURE 3. Microscopic structures of Sistotremastrum massonianum a Basidiospores; b Basidia; c Basidioles; d Hyphidia; e Hyphae in subiculum; f Section of hymenium.