Gerronema zhujian Q. Na, H. Zeng & Y.P. Ge, 2022

Na, Qin, Hu, Yaping, Zeng, Hui, Song, Zhizhong, Ding, Hui, Cheng, Xianhao & Ge, Yupeng, 2022, Updated taxonomy on Gerronema (Porotheleaceae, Agaricales) with three new taxa and one new record from China, MycoKeys 89, pp. 87-120 : 87

Gerronema zhujian Q. Na, H. Zeng & Y.P. Ge sp. nov.

Figs 8 , 9 , 10

Diagnosis.

Pileus fuscous and densely covered with tiny, deep brown fur or scales, distinctly radially striped with darkened lines. Stipe white, upper part slight brown when old. Cheilocystidia present. Pileipellis without coarse excrescences.

Holotype.

China. Fujian Province, Nanping City, Wuyi Mountain, 25 Jul. 2020, Qin Na, Yupeng Ge, Yaping Hu, Hui Zeng, and Zewei Liu, FFAAS0376 (collection no. MY0553).

Etymology.

The name refers to the centrally depressed, umbilicate basidiocarps, which resemble an eye or a loudspeaker; zhujian is a mythical one-eyed Chinese creature who is usually very noisy, like a walking loudspeaker.

Description.

Pileus 8.6-18.5 mm in diam., convex to broadly convex, papillate, applanate and centrally depressed, subumbilicate to umbilicate with age, pellucid-striate to rugulo-striate, or sulcate, always ± distinctly radially striped with darkened lines, fuliginous-fuscous (2F8) or fuscous (4F8) at center when young, grayish white (3B1) towards the margin, fading to brown (3F8) at the center, yellowish-brown (4E8) towards the margin, densely covered with tiny, deep brown (4F4) fur or scales, slightly sparse with age, with a slightly involuted margin. Context white, thin, tough. Lamellae subdecurrent to decurrent, moderately broad, pure white to yellowish-white (4A2), edges concolorous with the sides. Stipe 19.0-25.0 × 1.0-1.5 mm, central, cylindrical, almost equal above, white, slight brown (8D3-8D4) in upper part when old, fibrous, hollow, pruinose, base slightly swollen with tiny, white fine hairs. Odorless, taste mild.

Basidiospores [80/4/3] (6.3) 6.7-7.4-8.0 (8.5) × (3.2) 3.7-4.1-4.6 (4.8) μm [Q = 1.64-2.07, Q = 1.81 ± 0.076] [holotype [40/2/1] (6.3) 6.6-7.4-7.9 (8.3) × (3.2) 3.7-4.0-4.5 (4.6) μm, Q = 1.69-2.07, Q = 1.82 ± 0.087], narrowly ellipsoid to cylindrical, hyaline, guttulate, thin-walled, inamyloid. Basidia 28-40 × 6-9 μm, hyaline, clavate, 4-spored. Cheilocystidia 29-46 × 7-13 μm, subfusiform, clavate, apex usually swollen, hyaline. Pleurocystidia absent. Lamellar trama subregular; hyphae 3-8 μm wide, thin-walled, hyaline, inamyloid. Pileus trama subregular, sarcodimitic. Pileipellis hyphae 3-6 μm wide, a cutis, light yellow (2B2); terminal elements utriform or clavate, 25-49 × 6-9 μm, light yellowish brown (2C4) to yellowish brown (2C6) pigmented, especially in the apex; true pileocystidia absent. Hyphae of the stipitipellis 2-8 μm wide, hyaline, smooth; caulocystidia long cylindrical, sometimes with rounded apex, 27-47 × 4-8 μm, hyaline, thin-walled. All tissues nonreactive in iodine. Clamps present in all tissues.

Habit and habitat.

Solitary to scattered on rotten wood, branches, and twigs in Theaceae, Fagaceae, Symplocaceae, Lauraceae, Aquifoliaceae, Ericaceae, and Pinaceae mixed forests. Subtropical monsoon climate, subtropical humid climate or subtropical maritime monsoon climate.

Other specimens examined.

Anhui Province, Chizhou City, Shitai County, Dayan Village, Guniujiang National Natural Reserve, 26 Jul 2019, Qin Na, Yupeng Ge, Hui Zeng, Junqing Yan, and Liangliang Qi, FFAAS0364 (collection no. MY0256); Fujian Province, Sanming City, Mingxi County, Junzifeng National Natural Reserve, 23 Jun 2021, Qin Na, Yupeng Ge, Liangliang Qi, and Binrong Ke, FFAAS0370 (collection no. MY0296).

Remarks.

Gerronema zhujian is unique among Gerronema on account of its fuscous pileus with tiny, dark brown fur or scales, its distinctly radially striping with darkened lines, cheilocystidia present and pileipellis without coarse excrescences. Two species of Omphalina characterized by dark pigments in the pileus- Omphalina depauperata (Singer) Raithelh. and O. subpallida (Singer) Raithelh., formerly named G. subpallidum Singer and G. depauperatum Singer, respectively, have been described from Argentina. These two species most closely resemble G. zhujian but differ in having a hyaline or white stipe, ellipsoid basidiospores, and no cheilocystidia ( Singer 1970). Gerronema chrysocarpum is closely allied to G. zhujian on the basis of the dark brown coloration of the umbilicus of its pileus, its whitish stipe, and similarly shaped basidiospores ( Liu 1995). This taxon differs from G. zhujian in having a viscid and glabrescent pileus, pale orange lamellar margin, and pleurocystidia ( Liu 1995). Other species of Gerronema , such as G. nemorale and G. strombodes , have 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).

Figures

Figure 8. Fresh basidiomata of Gerronema zhujian Q. Na, H. Zeng & Y. P. Ge. a-b FFAAS 0364 c-d FFAAS 0376 (Holotype) e-f FFAAS 0370. Scale bars: 10 mm (a-f). Photographs a-b, e-f by Liangliang Qi c-d by Junqing Yan.

Figure 9. Microscopic features of Gerronema zhujian Q. Na, H. Zeng & Y. P. Ge. (FFAAS 0376, Holotype) a-e basidiospores f basidia g-i cheilocystidia j lamellar trama k pileipellis l stipitipellis and caulocystidia. Scale bars: 5 μm (a-e); 10 μm (f-l).

Figure 10. Morphological features of Gerronema zhujian Q. Na, H. Zeng & Y. P. Ge. (FFAAS 0376, Holotype) a basidiomata b basidia c basidiospores d cheilocystidia e stipitipellis and caulocystidia f pileipellis. Scale bars: 10 mm (a); 10 μm (b-f). Drawing by Qin Na and Yupeng Ge.