Melanoleuca griseoflava X.D. Yu & H.B. Guo, 2021

Pei, Ying, Guo, Hong-Bo, Liu, Tie-Zhi, Qin, Wei-Qiang, Zhao, Di, Qi, Xiao-Jian & Yu, Xiao-Dan, 2021, Three new Melanoleuca species (Agaricales, Basidiomycota) from north-eastern China, supported by morphological and molecular data, MycoKeys 80, pp. 133-148 : 133

Melanoleuca griseoflava X.D. Yu & H.B. Guo sp. nov. Figs 4 , 6d-g

Etymology.

The epithet refers to the colour of the pileus which is greyish-brown.

Diagnosis.

The new species is distinguished from M. exscissa in having adnexed to adnate lamellae and fusiform cheilocystidia.

Type.

China. Liaoning Province: Shenyang City, Tianzhu Mountain , on the soil in woods, 31 Aug 2019, X.D. Yu (holotype: SYAU-FUNGI-062) .

Description.

Pileus 35-60 mm diam., flat at first, then gradually depressed, margin slightly inflexed when mature, surface fibrillose, greyish-brown (4B3 to 4B5), becoming deep yellow (4C6 to 4C8) at centre. Lamellae crowded, adnexed to adnate, white, 2.5-3.0 mm broad, with lamellulae, edge entire. Stipe cylindrical, 30-50 mm long × 3-5 mm diam., central, somewhat broadened at the base, fibrous, expanded at base, solid, surface yellowish-grey to greyish at first (4B2 to 4C2), becoming yellowish-brown (5E7 to 5E8) with age, striate, with whitish basal tomentum. Pileus context up to 10 mm thick near stipe attachment, thin at margin, greyish-yellow to yellowish-grey (4B4 to 4B2), yellowish-grey (4B2) in stipe cortex, whitish in stipe base. Odour none, taste mild. Spore deposit white.

Basidiospores (234/10/8) (5.0) 6.0-7.2 (8.0) × 4.0-5.0 (6.0) μm, av. 6.5 × 4.5 μm, Q = (1.30)1.45-1.55 (1.60), ellipsoid, hyaline, amyloid, ornamentation verruculose, warts with ridges, almost reticulate. Basidia (18) 20-25 (28) × (4.0) 5.0-6.5 (7.0) μm, av. 22 × 6.0 μm, clavate, 4-spored, occasionally 2-spored, hyaline. Cheilocystidia (40) 45-55 (60) × (6.0) 8.0-12.0 (15.0) μm, fusiform, thin-walled, with encrusted crystals at apex, abundance. Pleurocystidia scattered, similar to cheilocystidia. Hymenophoral trama 90-150 μm broad, regular with thin-walled hyphae 3.0-14.0 μm diam., hyphae not pigmented, lamella edge sterile, Subhymenium poorly developed. Pileipellis a cutis of numerous repent branched hyphae 7.5-10.5 μm wide, thin-walled, pigmented with light violet. Stipitipellis hyphae 3-10.0 μm diam., smooth, thin-walled, pigmented. Caulocystidia of two types of cells, (1) 40-90 × 6.0-10.0 μm, fusiform, thin-walled, some with encrusted crystals at apex, similar to cheilocystidia; (2) 30-40 × 7.0-10.0 μm, clavate, thin-walled, without crystals. Clamp connections absent.

Habit, habitat and distribution.

Solitary, saprotrophic on the soil, on the grass, on roadsides, in woods. Known from north-eastern China.

Additional specimens examined.

China. Liaoning Province: Shenyang City, Tianzhu Mountain, on the soil in woods, 31 Aug 2019, X.D. Yu (SYAU-FUNGI-063); Fuxin City, Haitang Mountain , on roadsides, 20 Jul 2019, H.B. Guo (SYAU-FUNGI-061) . Inner Mongolia: Chifeng City, Linxi County, Xinlin Town , Dauran Village , alt. 1286 m, 43.08°N, 118.07°E, 22 Aug 2017, X.D. Yu (SYAU-FUNGI-064). Chifeng City, Karakqin Banner, Maanshan, 2 Sep 2019, T.Z. Liu & Y.M. Gao (CFSZ 21439) .

Figures

Figure 4. Melanoleuca griseoflava (holotype, SYAU-FUNGI- 062) A macroscopic habit B, C surface of basidiospores D hymenial cystidia with encrusted crystals at apex. Scale bars: 1 cm (A); 5 μm (B, C); 10 μm (D).

Figure 6. Line drawings of the three new Melanoleuca species A-C Melanoleuca chifengense (holotype, SYAU-FUNGI- 059) A basidiospores B, C basidia and basidioles D-G Melanoleuca griseoflava (holotype, SYAU-FUNGI- 062) D basidia and basidioles E caulocystidia F basidiospores G cheilocystidia H, I Melanoleuca pallidorosea (holotype, SYAU-FUNGI- 058) H basidiospores I basidia and basidioles. Scale bars: 10 μm.