Scleroderma yunnanense Y. Wang

(2.6) Scleroderma yunnanense Y. Wang, in Zhang, Xu, Liu, He, Wang, Wang & Ji, Mycotaxon 125: 195 (2013) (Fig. 15) Description:— Basidiomata small to medium-sized, 27–65 mm in diameter, 18–45 mm in height, subglobose to tuberiform at first, becoming stelliform following dehiscence, mostly sessile, rarely shortly stipitate; odor fungal and pleasant, similar to potatoes; taste pleasant and sweet. Peridium leathery, 2–4 mm thick, merino white (#F9F5EC), lotus-root orange (#F5E9D9) to butter orange (#F2DF8F) usually without a color change after damaged, occasionally turning reddish after damaged, with flaky, granular to furfuraceous, concolorous or dull dirty orange (#EBD087), light brown (#B39966) to dirty brass brown (#B47F5A) squamules. Gleba compact at first, becoming pulverulent, flint brown (#736960), coal blue (#40474D) to dull black (#0B0C0E). Basal rhizomorphs abundant, whitish to yellowish. Basidiospores {40/3/3} 8–14 (14.5) [11.11 ± 1.98, 13.00] µm in diameter including ornamentation, mostly globose, rarely subglobose, thick-walled, with echinulate to subreticulate ornamentation 0.5–2.5 µm high, brownish to purplish, often surrounded by remnants of placental cells 1.5–2.5 μm wide. Basidia 20–40 × 7–8.5 μm, clavate, four- to eight-spored, thin-walled, nearly colorless. Gleba trama composed of 2–5 μm wide, thin-walled, nearly colorless, compact, moderately branching, subregularly arranged to interwoven hyphae occasionally with clamp connections. Peridial squamules composed of 2–5 μm wide, thin- to slightly thick-walled, brownish, moderately compact, moderately to frequently branching, interwoven hyphae occasionally with clamp connections. Peridial trama composed of 2–7 μm wide, thin- to slightly thick-walled, nearly colorless to slightly brownish, compact, frequently branching, subregularly arranged hyphae occasionally with clamp connections. Habits and distribution:— Gregarious, on soil, in tropical to subtropical forests, associated with plants of Betulaceae, Fabaceae, Fagaceae and Pinaceae. Currently known from Asia (China, India, Japan & Thailand) with molecular evidence. Collections examined:— China, Guangdong Province, Guangzhou City, Tianhe District, South China Agricultural University, Arboretum, 23°09'27"N, 113°21'22"E, elevation 40 m, May 24, 2023, Jia Y. Lin & Kun L. Yang, K23243 (HTBM0758). China, Chongqing Municipality, exact location unknown, June 2, 2023, Kun L. Yang, kindly donated by anonymous net friends, S2385 (HTBM0328). China, Guangdong Province, Guangzhou City, Zengcheng District, Jiaoshiling Forest Park, 23°16'55"N, 113°51'23"E, elevation 180 m, July 6, 2023, Jia Y. Lin & Kun L. Yang, L23158 (HTBM1110) & L23163 (HTBM1115). China, Jiangxi Province, Shangrao City, Qianshan County, exact location unknown, June 10, 2023, Dan-Ying Liu, Kun L. Yang et al., S23117 (HTBM0360). China, Chongqing Municipality, Bishan District, exact location unknown, June 10, 2023, Zhi Ci Liu Nian, Kun L. Yang et al., S23120 (HTBM0363). China, Guangdong Province, Guangzhou City, Huangpu District, Jiangdong Village, Boluoshan Hill, 23°11'32"N, 113°32'25"E, elevation 150 m, June 13, 2023, Zhen-Chao Liu & Kun L.Yang, S23136 (HTBM0379). China, Guangdong Province, Jieyang City, Jiexi County, Daxi Town, Daxipu Village, 23°11'32"N, 113°32'25"E, elevation 150 m, June 14, 2023, Xiu-Hui Li, Kun L. Yang et al., S23150 (HTBM0393). China, Guangdong Province, Guangzhou City, Baiyun District, Baiyun Mountain Scenic Area, 23°13'N, 113°18'E, elevation 95 m, June 20, 2023, Yu-Rong Liang, ACE64 - S23176 (HTBM0419). China, Guangdong Province, Guangzhou City, Baiyun District, Baiyun Mountain Scenic Area, 23°12'26"N, 113°18'04"E, elevation 100 m, July 28, 2023, Jia Y. Lin, L23217 (HTBM1169). China, Guangdong Province, Guangzhou City, Baiyun District, Baiyun Mountain Scenic Area, 23°12'33"N, 113°18'20"E, elevation 100 m, August 3, 2023, Jia Y. Lin, L23257 (HTBM1209). China, Jiangsu Province, Nanjing City, Xuanwu District, Zijinshan Mountain, exact location unknown, August 11, 2023, Xia Chen, Jia Y. Lin & Kun L. Yang, ChenXia567 - S23373 (HTBM1484). China, Yunnan Province, Gejiu City, bought from a free market, July 2, 2024, Zhu L. Yang, Yang7155 (HKAS137567). Notes:— Our basidiospore size measurements are significantly larger than those in the protologue of S. yunnanense (Zhang et al. 2013: up to 9.5 µm wide including ornamentation) and a description on Japanese collections of S. yunnanense (Kasuya et al. 2023: up to 8 µm in diameter including ornamentation). We also found that basidiospores with a diameter more than 12 µm were quite common in mature collections with a pulverulent gleba. However, in the current phylogeny (Fig. 1), our collections show no obvious genetic distances from both the holotype of S. yunnanense (KUN-HKAS79633) and one collection cited in the Japanese description (TNS F-82294), suggesting them as conspecific. Scleroderma yunnanense is a common and high-yielding species in China, locally known as “Niu Yan Jing Jun (ox-eye mushrooms)” and “Shi Tou Gu (stone mushrooms)”, frequently gathered, consumed and highly prized by the people. Kun L. Yang has eaten it for several times, found it quite tasty without experiencing any trouble (Fig. 15h–i). Although this species has been detected in some mushroom poisoning incidents in China, it is considered an irrelevant species safe for eating in most cases at the moment (e.g. Li et al. 2024), obviously easy to be confused with some co-occurring similar but poisonous Scleroderma species, such as S. cepa. Scleroderma yunnanense is also eaten by people out of China, such as Indians (Tudu et al. 2024).