Panus minisporus L. Yue, J. J. Hu, B. Zhang & Y. Li, 2024

Yue, Lei, Chen, Junliang, Tuo, Yonglan, Qi, Zhengxiang, Liu, Yajie, He, Xiao Lan, Zhang, Bo, Hu, Jiajun & Li, Yu, 2024, Taxonomy and phylogeny of Panus (Polyporales, Panaceae) in China and its relationship with allies, MycoKeys 105, pp. 267-294 : 267-294

Panus minisporus L. Yue, J. J. Hu, B. Zhang & Y. Li sp. nov.

Figs 2 , 3

Etymology.

The epithet ‘ minisporus ’ refers to the small basidiospores of the new species.

Diagnosis.

This species is distinguished from closed species by the cyathiform or flared and reddish-brown (N 60 Y 90 M 60) pileus, white or dirty white (N 00 Y 10-20 M 00 - 10) lamellae with cross-veins and two tiers of lamellulae, slender stipe, smaller basidiospores, wider generative hyphae and absence of sclerocystidia.

Holotype.

China. Guizhou Province: Qiannan Buyi and Miao Autonomous Prefecture , Libo County, Maolan National Nature Reserve , 25.32 ° N, 108.08 ° E, 8 August 2017, Jiajun Hu, FJAU 67792 (GenBank accession no.: ITS: PP 273980, PP 273981, PP 273982; nLSU: PP 273970, PP 273971, PP 273972; tef- 1 α: PP 590550, PP 590551, PP 590552).

Description.

Basidiomata solitary, large. Pileus 2.5–6.5 cm in diameter, thin, coriaceous, applanate, cyathiform or flared, reddish-brown (N 60 Y 90 M 60), darker at the centre, covered with reddish-brown (N 60 Y 90 M 60) puberulent, stripe dense and slender, radially parallel distributed, margin integer and ciliate slightly dense. Lamellae decurrent, crowded, white or dirty white (N 00 Y 10-20 M 00 - 10), with cross-veins and two tiers of lamellulae, edge entire. Stipe 4.4–9 × 0.2–0.5 cm, inverted clavate, central, solid, coriaceous, surface reddish-brown (N 60 Y 90 M 60) or more often darker, with dense velutinus, slightly expanded at the base. Pseudosclerotium absent. Context thin, up to 1 mm thick, white (N 00 Y 10 M 00), coriaceous, consisting of a dimitic hyphal system with skeletal hyphae.

Generative hyphae 3–5 (7) μm diameter, cylindrical, not inflated, hyaline, thin-walled, frequently branched, with prominent clamp connections. Skeletal hyphae 2–3 μm diameter, sinuous cylindrical, hyaline, with a thick-walled and continuous lumen, unbranched. Basidiospores 4.5–5 (5.5) × 2.5-3 μm (n = 40, lm = 5 μm, wm = 3 μm, Q = 1.5–1.83, q = 1.67), ellipsoid to oblong, smooth, hyaline, thin-walled. Basidia (16) 19–26 × 5–6 μm, clavate or elongated, bearing 4 sterigmata. Lamella-edge sterile, with small cheilocystidia. Cheilocystidia crowded, 16–22 × 5–6 μm, with median constriction, nodulose-clavate, fusoid, irregular, hyaline, thin-walled. Sclerocystidia absent. Hymenophoral trama irregular, radiate construction, hyaline, similar in structure to the context. Pileipellis on epicutis, made up of thick-walled generative hyphae, 3–5.5 (7) μm diameter, occasionally bunched, not inflated, light brown. Stipitipellis similar to pileipellis.

Ecology.

Solitary on rotten wood in broad-leaved forest.

Distribution.

China (Guizhou Province).

Notes.

This species is characterised by the reddish-brown pileus and stipe, white or dirty white lamellae with cross-veins and two tiers of lamellulae, slender stipe, smaller basidiospores and absence of sclerocystidia.

Panus minisporus is close to P. velutinus and P. similis in morphology, because of the velutinate pileus and slender stipe. However, the pileus and stipe of P. minisporus are both reddish-brown, which is different from the pale greyish-cinnamon to rufous or tawny-brown tints of P. velutinus and the cinnamon-brown to dark chestnut-brown, with violaceous or purplish tints of P. similis . Meanwhile, the lamellae of P. minisporus are white or dirty white, with cross-veins and two tiers of lamellulae, but the lamellae of P. velutinus and P. similis have no cross-veins and with 3 or 4 and 5 tiers of lamellulae, respectively. In addition, the pseudosclerotium of P. minisporus is absent, but P. velutinus and P. similis often have distinct pseudosclerotium. In terms of micromorphology, P. minisporus has smaller spores and Q values, wider generative hyphae and absent sclerocystidia, all of which can be distinguished from P. velutinus and P. similis .

Figures

Figure 2. Habitat of Panus minisporus (FJAU 67792, holotype) A basidiocarp B pileus C lamellae D stipe. Scale bars: 1 cm.

Figure 3. Microscopic characteristics of Panus minisporus (FJAU 67792, holotype) A basidiospores B cheilocystidia C basidia D generative hyphae of context E pileipellis hyphae F skeletal hyphae of context. Scale bars: 10 μm.