Gerronema brunneosquamulosum Q.Na & Y.P.Ge, 2024

Na, Qin, Zeng, Hui, Hu, Yaping, Ding, Hui, Ke, Binrong, Zeng, Zhiheng, Liu, Changjing, Cheng, Xianhao & Ge, Yupeng, 2024, Morphological and phylogenetic analyses reveal five new species of Porotheleaceae (Agaricales, Basidiomycota) from China, MycoKeys 105, pp. 49-95 : 49

Gerronema brunneosquamulosum Q.Na & Y.P.Ge sp. nov.

Figs 5 , 6 , 7

Diagnosis.

Differs from G. zhujian in having a fuscous stipe densely covered with deep-brown pubescence or scales and by the presence of large basidiospores.

Holotype.

China. Zhejiang Province: Baiyun National Forest Park, Liandu District, Lishui City, 2 Aug 2021, Qin Na, Yupeng Ge, and Hui Zeng, FFAAS1032 (collection number MY0481).

Etymology.

Name refers to the pileus and stipe covered with dark-brown scales.

Description.

Pileus 4.5-42.0 mm in diam., applanate and centrally depressed, subumbilicate to umbilicate when young, concave to deeply infundibulate with age, pellucid-striate or sulcate, always ± distinctly radially striped with darkened lines, Buffy Brown (XL17′′′k) at the centre, Olive Buff (XL21′′′d) in margin when young, Olive Brown (XL17′′′k), Clove Brown (XL17′′′m), Light Greyish-Olive (XLVI21′′′′b) in margin with age, densely covered with tiny, Warm Blackish-Brown (XXXIX1′′′m) granules, pubescence or scales, slightly sparse with age, dry, lustreless, with a slightly involuted margin. Context white, thin, tough. Lamellae narrowly adnexed to subdecurrent, moderately broad, pure white, edges concolorous with the sides. Stipe 6.0-32.0 × 1.5-2.0 mm, central, cylindrical, almost equal above, white, densely covered with Warm Blackish-Brown (XXXIX1′′′m) scales, hollow, base Light Seal Brown (XXXIX9′′′m), slightly swollen with tiny, inconspicuous fine white hairs. Odourless. Taste mild.

Basidiospores [60/3/2] (9.0) 9.2-10.0-11.2 (12.9) × (4.9) 5.2-5.8-6.6 (7.2) μm [Q = 1.54-1.91, Q = 1.73 ± 0.097] [holotype [40/2/1] (9.0) 9.2-10.2-11.2 (12.9) × (5.3) 5.5-5.9-6.5 (7.2) μm, Q = 1.54-1.90, Q = 1.71 ± 0.086], ellipsoid to narrowly ellipsoid, hyaline, guttulate, thin-walled, inamyloid. Basidia 22-39 × 7-9 μm, hyaline, clavate, 2- or 4-spored, sterigmata 2.3-6.0 × 0.8-2.2 μm. Cheilocystidia 23-59 × 6-9 μm, subfusiform, clavate, apex usually swollen, hyaline. Pleurocystidia absent. Lamellar trama subregular; hyphae 2-7 μm wide, thin-walled, hyaline, inamyloid. Pileus trama subregular, sarcodimitic. Pileipellis hyphae 3-7 μm wide, a cutis, light yellow (2B2); terminal elements clavate or utriform with rounded apex, 53-95 × 7-16 μm, Dark Citrine (IV21m), Olive Brown (XL17′′′k) to Clove Brown (XL17′′′k) pigmented; true pileocystidia absent. Hyphae of the stipitipellis 5-11 μm wide, hyaline, smooth; caulocystidia long cylindrical, sometimes with rounded apex, 40-76 × 5-12 μm, hyaline, thin-walled. All tissues non-reactive in iodine. Clamps present in all tissues.

Habit and habitat.

Solitary to scattered on rotten wood, branches and twigs in Acer , Ginkgo , Liriodendron , Picea and Tsuga .

Known distribution.

Fujian Province, Zhejiang Province, China.

Additional material examined.

China. Fujian Province: Wuyi Mountain, Nanping City , 13 Aug 2021, Qin Na, Yupeng Ge, Junqing Yan, Hui Zeng, and Zewei Liu, FFAAS1033 (collection number MY0571) .

Notes.

Gerronema brunneosquamulosum is unique amongst members of Gerronema on account of its fuscous pileus and stipe with dark-brown to blackish-brown pubescence or scales, larger basidiospores and a dark-pigmented pileipellis. Gerronema zhujian , reported from Anhui and Fujian Provinces in China, is the most closely allied congener of G. zhujian on the basis of the brown colouration of the umbilicus of its pileus, its whitish stipe and similarly-shaped cheilocystidia and terminal elements of the pileipellis ( Na et al. 2022a). This taxon differs from G. brunneosquamulosum in having a pruinose white stipe, subdecurrent to decurrent lamellae and possessing smaller basidiospores ( Na et al. 2022a). Two species of Omphalina Quél., characterised by dark pigments in the pileus, have been described from Argentina- Omphalina depauperata (Singer) Raithelh. and O. subpallida (Singer) Raithelh., formerly named Gerronema subpallidum Singer and G. depauperatum Singer, respectively. These two species most closely resemble G. brunneosquamulosum , but differ in having an unornamented stipe, ellipsoid basidiospores and no cheilocystidia ( Singer 1970). Other species of Gerronema , such as G. nemorale and G. strombodes , are well characterised with a distinctly yellow, yellowish-orange, olive-yellow to yellowish-brown pileus and their micromorphological features are also different ( Singer 1970; Antonín et al. 2008; Latha et al. 2018). Species of Trogia , especially Trogia fulvochracea Corner (p.31) and Trogia mycenoides (p.53) Corner, share some similarities with the new taxon ( Corner 1991). Trogia fulvochracea , however, has a fulvous or cinnamon-ochraceous pileus, a smooth white stipe and smaller basidiospores (7-9.5 × 4.5-6.0 μm). Trogia mycenoides differs in having a smaller pileus (5-30 mm in diam.), ellipsoid basidiospores and clavate to subglobose cheilocystidia; in addition, true pileocystidia are present, but are soon evanescent ( Corner 1991).

Figures

Figure 5. Basidiomata of Gerronema brunneosquamulosum A, B FFAAS 1032, holotype C, D collection FFAAS 1033 E, F pileus with granules, fur or scales G, H stipe covered with dark brown scales. Scale bars: 10 mm (A-E); 5 mm (F-H).

Figure 6. Morphological features of Gerronema brunneosquamulosum (FFAAS 1032, holotype) A basidiomata B basidia C basidiospores D cheilocystidia E caulocystidia F pileipellis. Scale bars: 10 mm (A); 10 μm (B-F).

Figure 7. Microscopic features of Gerronema brunneosquamulosum (FFAAS 1032, holotype) A-E basidiospores F basidia G-J cheilocystidia K lamellar trama L pileipellis and pileocystidia M caulocystidia. Scale bars: 5 μm (A-E); 10 μm (structures A - K, M were stained with 1 % Congo Red aqueous solution and L in 5 % KOH aqueous solution before photographing).