Gyroporus flavocyanescens Yan C. Li, C. Huang & Zhu L. Yang, 2021

Huang, Cong, Zhang, Ming, Wu, Xing-Liang, Wu, Gang, Xu, Jian-Ping, Yang, Zhu L. & Li, Yan-Chun, 2021, Cyanescent Gyroporus (Gyroporaceae, Boletales) from China, MycoKeys 81, pp. 165-183 : 165

Gyroporus flavocyanescens Yan C. Li, C. Huang & Zhu L. Yang sp. nov.

Figs 3d , 6

Etymology.

The epithet Gyroporus flavocyanescens refers to the flavous basidiomata with blue discolouration when bruised.

Type.

China. Guizhou Province: Pan County, alt. 1700 m, 2 Jul 2008, X.L. Wu 1182 (KUN-HKAS 76966, GenBank accession numbers: MW440550 for ITS, MW442950 for nrLSU, MW452613 for atp6) .

Diagnosis.

Differs from other cyanescent species in Gyroporus by its initially flavous to dull yellow or grey-yellow and then grey-orange to greyish-orange pileus, nearly glabrous or somewhat fibrillose to finely tomentose pileal surface, relatively small basidia measuring 21-30 × 9-11 µm, slender basidiospores measuring 8-10 × (5) 5.5-6.5 µm and relatively short and slender chelocystidia measuring 26-35 × 5-9 μm.

Description.

Pileus 6-10 cm in diam., hemispherical to sub-hemispherical when young, applanate to plano-convex when mature, flavous (3B3-4) to dull yellow or grey-yellow (2B4-5) when young, grey-orange (5B4-5) to greyish-orange (5B3-4) when mature; surface dry, nearly glabrous or somewhat fibrillose to finely tomentose, margin incurved and slightly extended; context whitish (1A1), staining strong dark blue or indigo-blue (24D4-8) when bruised. Hymenophore adnate when young, depressed around apex of stipe when mature; surface white (1A1) when young and then grey (1B1) to cream when mature, staining cyanine blue (24D4-6) to porcelain blue (23C5-6) when bruised; pores angular to roundish, 1-2 per mm; tubes 4-10 mm long, whitish (1A1), staining cyanine blue to porcelain blue when bruised. Stipe 4-6 × 2.5-4 cm, clavate, enlarged downwards; surface roughened, white to cream when young and then pale yellow (2A3-5) to concolorous with pileal surface when mature or aged; context white to cream or yellowish, spongy when young and then hollow in age, staining cyanine blue to porcelain blue when bruised. Odour indistinct and taste mild.

Basidia 21-30 × 9-11 µm, clavate, hyaline in KOH and yellowish in Melzer’s Reagent, 4-spored. Basidiospores [60/3/2] 8-10 × (5) 5.5-6.5 µm, (Q = 1.45-1.81, Qm = 1.59 ± 0.12), smooth, ellipsoid to somewhat broadly ellipsoid, hyaline to yellowish in KOH and primrose yellow to yellow in Melzer’s Reagent. Cheilocystidia 26-35 × 5-9 μm, clavate to subfusiform, thin-walled, hyaline in KOH and yellowish to yellow in Melzer’s Reagent. Pleurocystidia not observed. Tube trama composed of 5-9 μm wide interwoven hyphae, hyaline to yellowish in KOH, yellowish to brownish-yellow in Melzer’s Reagent. Squamules on pileus composed of 8-17 μm wide interwoven hyphae, hyaline to yellowish in KOH, yellowish to brownish-yellow in Melzer’s Reagent; terminal cells 90-140 × 9-17 μm, clavate to subcylindrical. Clamp connections frequently present in all tissues.

Additional specimen examined.

China. Guizhou Province: Pan County, alt. 1700 m, 2 Jul 2008, X.L. Wu 1187 (KUN-HKAS 77804, GenBank accession numbers: MW440551 for ITS, MW442951 for nrLSU).

Habitat and distribution.

Scattered on soil in the tropical forests dominated by Castanea sp. ( Fagaceae ) and Quercus sp. ( Fagaceae ). Currently known from south-western China.

Note.

Gyroporus flavocyanescens is characterised by the flavous to dull yellow or grey-yellow and then grey-orange to greyish-orange pileus, the nearly glabrous to fibrillose to finely tomentose pileal surface, the slightly extended pileal margin, the white pileal context staining strong dark blue or indigo-blue when bruised, the white to grey or cream to yellowish hymenophore staining cyanine blue to porcelain blue when bruised, the white to cream and then pale yellow to flavous stipe, the spongy and then hollow context in the stipe, the frequent clamp connections in all tissues, the ellipsoid to somewhat broadly ellipsoid basidiospores and the distribution in tropical forests dominated by plants of the family Fagaceae .

Gyroporus flavocyanescens is morphologically similar to G. lacteus and G. pseudolacteus . Indeed, they are phylogenetically related to each other, based on our analysis of combined nrLSU + ITS dataset (Fig. 2 ), though it should be noted that the bootstrap support is relatively low for the relationship with G. lacteus (87%). Gyroporus lacteus has large basidiomata (9-17 cm in diam.), ochraceous pileus with scaly tomentose squamules and large cheilocystidia up to 50 × 10 µm ( Vizzini et al. 2015). Gyroporus pseudolacteus has a whitish to cream white and then more or less yellowish-ochre pileus, relatively large basidia measuring 35-43 × 10-14 µm and large cheilocystidia measuring 35-55 × 8-12 µm ( Crous et al. 2017).

In this study, three cyanescent species of Gyroporus from China could be recognised and identified. For the convenience of identification of the species, a key is given below.

Figures

Figure 2. Maximum Likelihood phylogenetic tree of Gyroporus inferred from the combined (nrLSU + ITS) dataset. Bootstrap frequencies (> 50 %) are shown above supported branches. Newly-sequenced collections are indicated in bold. Species vouchers and countries of origin are provided after the species name successively.

Figure 3. a-c Gyroporus alpinus (KUN-HKAS 56318, type, photos by Y. C. Li) d Gyroporus flavocyanescens (KUN-HKAS 76966, type, photo by X. L. Wu) e-h G. brunneofloccosus (e KUN-HKAS 107735, photo by G. Wu f GDGM 77125, photo by J. Y. Xu g, h GDGM 74638, photos by J. Y. Xu). Scale bars: 2 cm.

Figure 6. Microscopic features of G. flavocyanescens (KUN-HKAS 76966, type) a basidia b basidiospores c cheilocystidia d pileipellis (squamules).