Steccherinum fragile Z.B. Liu & Y.C. Dai, 2021

Liu, Zhan-Bo & Dai, Yu-Cheng, 2021, Steccherinum fragile sp. nov. and S. subcollabens comb. nov. (Steccherinaceae, Polyporales), evidenced by morphological characters and phylogenetic analysis, Phytotaxa 483 (2), pp. 106-116 : 112-113

Steccherinum fragile Z.B. Liu & Y.C. Dai , sp. nov. ( Figs. 2–3 )

MycoBank no: MB 838236

Diagnosis:— Steccherinum fragile is characterized by an annual growth habit, resupinate basidiocarps with salmon to peach pores when fresh becoming cinnamon buff to pinkish buff upon drying, margin thin with distinct rhizomorphs, a monomitic hyphal system, generative hyphae thin- to distinctly thick-walled with simple septa, neither amyloid nor cyanophilous.

Etymology:—‘ Fragile ’ (Lat.) refers to the species having fragile basidiocarps.

Type:— CHINA. Yunnan Province, Puer, Puer Forest Park , Xiniuping , on rotten angiosperm wood, 17 August 2019, Y.C. Dai, Dai 20479 (Holotype, BJFC032147 ) .

Description:— Basidioma annual, resupinate, separable from the substrate, very soft when fresh, soft to fragile when dry, up to 4 cm long, 2 cm wide, and approximately 1 mm thick at center; margin thin with distinct rhizomorphs; rhizomorphs salmon to peach when fresh, becoming cinnamon buff upon drying; pore surface salmon to peach when fresh, becoming cinnamon buff to pinkish buff when dry; pores angular, 4–5 per mm; dissepiments thin, entire to slightly lacerate; subiculum very thin to almost absent; tubes concolorous with poroid surface, less than 1 mm long.

Hyphal system:—Monomitic; generative hyphae thin- to distinctly thick-walled, simple septate; all hyphae IKI–, CB–, unchanged in KOH.

Subiculum:—Generative hyphae hyaline to pale yellowish brown, thin- to thick-walled, frequently branched, interwoven, 2.5–6.5 μm in diam; irregular crystals rarely present.

Tubes:—Generative hyphae hyaline to pale yellowish brown, thin- to thick-walled, occasionally branched, interwoven, 2–6 μm in diam; irregular crystals rarely present; cystidia and cystidioles absent; basidia clavate, hyaline, thin-walled, bearing four sterigmata and a simple basal septum, 13–14 × 4–4.5 μm; basidioles barrel-shaped, 7–9 × 3–4.5 μm.

Basidiospores:—Ellipsoid, hyaline, thin-walled, smooth, occasionally with one or two guttules, IKI–, CB–, (2.6–)2.8–3.1 × (2–)2.1–2.2(–2.5) μm, L = 2.96 μm, W = 2.11 μm, Q = 1.24–1.47 (n = 60/2).

Additional specimen examined (paratype)— CHINA. Yunnan Province, Wenshan, Xichou County, Xiaoqiaogou Forest Farm , on ground of angiosperm forest, 29 June 2019, Y.C. Dai, Dai 19972 ( BJFC031646 ) .

Figures

FIGURE 2. A basidiocarp of Steccherinum fragile (Holotype, Dai 20479). Scale bar = 1.0 cm. Photo by: Yu-Cheng Dai.

FIGURE 3. Microscopic structures of Steccherinum fragile (Holotype, Dai 20479).a Basidiospores b Basidia c Basidioles d Hyphae from subiculum e Hyphae from trama. Drawings by: Zhan-Bo Liu.