Polyporus parvovarius H. Lee, N.K. Kim & Y.W. Lim

Index Fungorum number: IF552511 Facesoffungi number: FoF 2629

Etymology: referring to the similar but smaller basidiocarps compared to P. varius.

Holotype: SFC20120814-33

Basidiocarps annual, central stipitate; Pileus circular, plane then funnel-shaped, up to 35 mm diam., 1.5 mm thick; pileal surface light buff to brown, fibrillose with flattened, radially striate, glabrous; margin reddish-brown, enrolled, undulate. Hymonophore white, cream to brown; pores fine, rounded to angular, 6–7 per mm. Context in pileus pale buff, corky, up to 1 mm thick. Tube continuous with the context, up to 0.5 mm thick. Stipe central, brown to dark brown, smooth to longitudinally wrinkled, apex distinct from the pore, upper portion of blackish stipe usually covered by decurrent pores, up to 40 mm long and 2 mm thick. Hyphal system dimitic; generative hyphae hyaline in KOH, thin-walled, 2.5–3 μm in diam., septa with clamps, skeletal-binding hyphae thick-walled, aseptate, much branched, with tapering apices, 3–6 μm diam. Cystidia absent. Basidia clavate, 4-sterigmate (up to 3.4 μm), 23.8–26.3 × 7.4–8.5 μm, with a basal clamp. Basidiospores cylindric, hyaline, smooth, IKI-, 7.4–8.6 × 3.5–4.5 μm. L = 7.52 μm, W = 4.25 μm, Q = 1.78 (n = 20/1).

Habitat: solitary to gregarious on dead wood of hardwood.

Material examined: KOREA, Gyeongsangbuk-do, Ulleung-gun, Na-ri basin, on fallen hardwood branch, 14 August 2012, Y. W. Lim, W. J. Kim & S-Y. Oh (SFC20120814-33, holotype); KOREA, Gangwon-do, Inje-gun, on rotten wood below litter layer, 1 July 2014, Y. W. Lim & H. J. Cho (SFC2040701-19, paratype). GenBank numbers ITS:KY038466.

Notes: Polyporus parvovarius is similar to P. badius, P. elegans and P. varius in its central stipitate basidiocarps, blackish stipe, and microscopic features. Simple septate generative hyphae separate P. badius from the other species. P. parvovarius has larger basidia (23.8–26.3 × 7.4–8.5 μm) than P. elegans (15–20 × 6–7 μm) and P. varius (18–23 × 5–7 μm). Phylogenetic analysis of the ITS region showed that P. parvovarius is closely related to P. brevibasidiosus. However, they are distinguishable by pore, basidia, and basidiospore size. P. parvovarius has larger than those of P. brevibasidiosus.

Phylogram generated from maximum likelihood (RAxML) analysis based on ITS sequence data of Polyporus. Maximum likelihood bootstrap support values greater than 70% are indicated above or below the nodes and the new species is in bold. The tree is rooted with two Neofavolus species.


Polyporus parvovarius (SFC20120814-33, holotype). a fruiting bodies in the field (SFC20120814-33). b, c fruiting bodies in the field (SFC20140701-19). d pores of fruiting body (SFC20120814-33). e microscopic structure; basidiospores, basidia, generative hyphae and skeletal-binding hyphae.