Gerronema nemorale Har. Takah.

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 nemorale Har. Takah.

Figs 11 , 12 , 13

Description.

Pileus 3.0-19.0 mm in diam., hemispherical at first, then convex with a depressed center, applanated and deeply umbilicate with age, slightly striate at the margin in younger basidiomata, slightly translucently striate forming shallow grooves, greenish yellow (2E3), yellowish brown (2D5), olive brown (2E8), always deeper at the center, fading light yellow (5A2) towards the margin, finely tomentose when young, glabrescent with age, with a flat margin. Context white to light yellow, thin. Lamellae moderately distant to distant, decurrent, white or pale yellow (5A2), narrow, edges concolorous with the sides. Stipe 19.0-36.0 × 1.0-2.5 mm, almost equal, but swollen at the base, terete, slender, hollow, pruinose overall, glabrescent with age; base with conspicuous white mycelioid bristles. Odorless, taste mild.

Basidiospores [60/3/3] (6.8) 7.9-8.8-9.9 (10.7) × (3.7) 4.6-5.2-5.8 (6.3) μm [Q = 1.59-1.88, Q = 1.70 ± 0.065], narrowly ellipsoid or cylindrical, hyaline, guttulate, thin-walled, inamyloid. Basidia 32-46 × 6-9 μm, hyaline, clavate, 4-spored. Cheilocystidia 27-49 × 5-9 μm, abundant, irregularly cylindric or clavate, colorless. Pleurocystidia absent. Lamellar trama subregular; hyphae 3-9 μm wide, thin-walled, hyaline, inamyloid. Pileus trama subregular, sarcodimitic. Pileipellis hyphae 2-5 μm wide, light yellow (2B2), a cutis; terminal elements cylindric or clavate, 31-50 × 4-9 μm, light yellowish brown (2C4) to yellowish brown (2C6) pigmented, especially in the apex; true pileocystidia absent. Hyphae of the stipitipellis 3-6 μm wide, hyaline, smooth; caulocystidia cylindrical or broadly clavate, 32-48 × 5-8 μm, hyaline, thin-walled. All tissues nonreactive in iodine. Clamps present in all tissues.

Habit and habitat.

Solitary to caespitose on dead fallen twigs or rotten wood in mixed broadleaf-conifer forests from early spring to late autumn, common, especially in subtropical zones in China. Subtropical monsoon climate, subtropical humid climate subtropical maritime monsoon climate, or continental monsoon humid climate.

Distribution.

Known from Asia (Japan, Korea, Pakistan).

Specimens examined.

Anhui Province, Chizhou City, Shitai County, Dayan Village, Guniujiang National Natural Reserve, 7 Jun 2019, Qin Na, Yupeng Ge, Hui Zeng, Junqing Yan, and Liangliang Qi, FFAAS0377 (collection no. MY0113), Qingyang County, Miaoqian Town, 2 Sep 2019, Qin Na, Yupeng Ge, Hui Zeng, Junqing Yan, and Liangliang Qi, FFAAS0384 (collection no. MY0264); Fujian Province, Nanping City, Wuyi Mountain, 10 Aug 2021, Qin Na, Yupeng Ge, Junqing Yan, Zewei Liu, and Yulan Sun, FFAAS0410 (collection no. MY0549), Sanming City, Junzifeng National Natural Reserve, 22 Jun 2021, Qin Na, Yupeng Ge, Binrong Ke, and Liangliang Qi, FFAAS0390 (collection no. MY0287); Zhejiang Province, Lishui City, Qingyuan County, Wangmu, 26 May 2020, Qin Na, Yupeng Ge, Yaping Hu, Junqing Yan, and Zewei Liu, FFAAS0379 (collection no. MY0248); Jilin Province, Tonghua City, Jian City, Wunvfeng National Forest Park, 6 Jul 2021, Qin Na, Yupeng Ge, and Zewei Liu, FFAAS0392 (collection no. MY0364); Zhejiang Province, Lishui City, Longquan City, Zhuangbian Village, 10 Jul 2020, Qin Na, Yupeng Ge, Junqing Yan, and Zewei Liu, FFAAS0382 (collection no. MY0254), Liandu District, Baiyun National Forest Park, 2 Aug 2021, Qin Na, Zewei Liu, FFAAS0395 (collection no. MY0462), Qingtian County, Lanni Lake, 2 Jun 2021, Qin Na, Yupeng Ge, Junqing Yan, Yulan Sun, and Zewei Liu, FFAAS0388 (collection no. MY0273), Jinyun County, Dayang Mountain, 3 Jun 2021, Qin Na, Yupeng Ge, and Junqing Yan, FFAAS0389 (collection no. MY0276).

Remarks.

Having a sarcodimitic tissue structure, G. nemorale fits well within the currently restricted concept of the genus Gerronema ( Redhead 1986; Norvell et al. 1994). Gerronema nemorale seems to be rather common in the East Asian region ( Takahashi 2000; Antonín et al. 2008; Kim et al. 2014; Aqdus and Khalid 2021). Kim et al. (2014) has reported a basidiospore size of 6.0-8.2 × 3.5-4.8 μm for G. nemorale collected from Mount Halla (Jeju Island) in southwestern Korea, which is distinctly smaller than that of other specimens from Korea, Japan, Pakistan, and our collections ( Takahashi 2000; Antonín et al. 2008; Kim et al. 2014; Aqdus and Khalid 2021). Gerronema tenue Dennis, described from Venezuela, is allied with G. nemorale , but the latter differs in having a citrine yellow pileus, an insititious stipe, and lamellae edges without cheilocystidia ( Dennis 1961). Another similar species, G. corticiphilum Lj.N. Vassiljeva, described as G. corticiphila , has a rarely sulfurous-colored pileus and larger and narrower basidiospores (13-17 × 4-5 μm) ( Vassiljeva 1973). In addition, G. icterinum (Singer) Singer from South America, now treated as Trogia icterina (Singer) Corner, shows some similarities with G. nemorale but has veined and forked lamellae and lacks cheilocystidia ( Singer 1986). Another species of Trogia , T. mellea Corner, is also similar to G. nemorale , but can be easily distinguished from the latter in having no olivaceous tones on the pileus surface, a fuscous, pruinose pileus center and stipe, and subclavate or subventricose cheilocystidia ( Corner 1966).

Figures

Figure 11. Fresh basidiomata of Gerronema nemorale Har. Takah. a-b MY 0364 (Wunvfeng, Jian City, Liaoning Province) c MY 0113 (Guniujiang, Shitai County, Anhui Province) d MY 0264 (Miaoqian Town, Qingyang County, Anhui Province) e MY 0248 (Baishanzu, Qingyuan County, Zhejiang Province) f MY 0254 (Longquan Mountain, Longquan City, Zhejiang Province) g-h MY 0273 (Lanni Lake, Qingtian County, Zhejiang Province) i-j MY 0276 (Dayang Mountain, Jinyun County, Zhejiang Province) k-l MY 0462 (Baiyun Forest Park, Lishui City, Zhejiang Province) m-n MY 0287 (Junzifeng, Sanming City, Fujian Province) o MY 0549 (Wuyi Mountain, Nanping City, Fujian Province). Scale bars: 10 mm (a-o). Photographs a-e by Qin Na; f-g by Junqing Yan; h-i by Liangliang Qi; j-o by Yupeng Ge.

Figure 12. Morphological features of Gerronema nemorale Har. Takah. (FFAAS 0410) 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.

Figure 13. Microscopic features of Gerronema nemorale Har. Takah. (FFAAS 0410) 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).