Species diversity and taxonomy of Scytinostroma sensu stricto (Russulales, Basidiomycota) with descriptions of four new species from China Li, Yue Xu, Wei-Qi Liu, Shi-Liang Yang, Ning He, Shuang-Hui MycoKeys 2023 2023-06-13 98 133 152 81546DD1-EFA3-5DDA-B160-92CA0A65D4A7 Yue Li, S. L. Liu & S. H. He Yue Li, S. L. Liu & S. H. He 2023 Agaricomycetes Peniophoraceae Scytinostroma CoL Fungi Scytinostroma subrenisporum Russulales 0 133 Basidiomycota species subrenisporum sp. nov.   Fig. 8   Type.   China, Guizhou Province, Libo County, Maolan Nature Reserve, on dead angiosperm branch, 11 July 2017, He 4792 (BJFC 024311, holotype).   Figure 8.  Scytinostroma subrenisporum(from the holotypeHe 4792) abasidiomes bbasidiospores cbasidia dskeletal hyphae from hymenium eskeletal hyphae from subiculum. Scale bars: 1 cm( a); 10 µm( b-e).  Etymology. Refers to the morphological similarity and close phylogenetic relationship with  S. renisporum.  Fruiting body. Basidiomes annual, resupinate, widely effused, closely adnate, inseparable from substrate, membranaceous to coriaceous, first as small patches, later confluent up to 10 cm long, 2.5 cm wide, up to 100 µmthick in section. Hymenophore smooth, pale orange (5A3), light orange (5A4) to greyish orange [5B(5-6)], unchanged in KOH, not cracked; margin thinning out, adnate, fimbriate, white or concolorous with hymenophore surface. Context pale yellow.  Microscopic structures. Hyphal system dimitic. Context thickening, compact. Generative hyphae rare, scattered, simple-septate, colorless, thin-walled, 2-3 µmin diam., IKI-, CB-. Skeletal hyphae dominant, colorless to yellow, distinctly thick-walled, moderately branched, 1.5-2 µmin diam., dextriniod, CB+. Catahymenium composed of skeletal hyphae, basidia and basidioles. Skeletal hyphae abundant, similar to those in the context, but strongly dextrinoid, moderately branched with acute tips, 1.5-2 µmwide at lowest part. Gloeocystidia absent. Basidia subcylindrical, slightly curved, thin-walled, colorless, smooth, with four sterigmata and a basal simple septum, 35-45 x4.5-6.5 µm; basidioles in shape similar to basidia, but slightly smaller. Basidiospores ellipsoid to reniform, with a distinct apiculus, thin-walled, colorless, smooth, amyloid, CB-, (5.5-) 6-6.5 (-7) x(3.8-) 4-5 (-5.5) µm, L = 6.2 µm, W = 4.4 µm, Q = 1.35-1.45 (n = 60/2).  Additional specimens examined.   China, Anhui Province, Qimen County, Guniujiang Nature Reserve, on dead angiosperm branch, 8 August 2013, He1720 (BJFC 016187);  Fujian Province, Wuyishan County, Wuyishan Nature Reserve, on dead angiosperm branch, 3 October 2018, He5685 (BJFC 026747) & He5686 (BJFC 026748);  Guangxi Autonomous Region, Huanjiang County, Mulun National Nature Reserve, on dead angiosperm branch, 10 July 2017, He4751 (BJFC 024270);  Guizhou Province, Libo County, Maolan Nature Reserve, on angiosperm tree, 15 June 2016, He3792 (BJFC 022291);  Hunan Province, Guzhang County, Gaowangjie National Nature Reserve, on dead angiosperm branch, 3 August 2018, He5626 (BJFC 026688);  Jiangxi Province,  Ji'anCounty, Jinggangshan Scenic Spot, on dead angiosperm branch, 11 August 2016, He4303 (BJFC 023745); Lianping County, Jiulianshan Nature Reserve, on dead  Lianabranch, 14 August 2016, He4384 (BJFC 023825); Yifeng County, Guanshan Nature Reserve, on dead angiosperm branch, 9 August 2016, He4170 (BJFC 023612) & He4199 (BJFC 023641).  Notes.   Scytinostroma subrenisporumis characterized by the absence of gloeocystidia and ellipsoid to reniform basidiospores. In the phylogenetic tree (Fig. 1),  S. subrenisporumis closely related to  S. acystidiatumand  S. renisporum.  Scytinostroma acystidiatumthat was recently described from China, is similar to  S. subrenisporumby sharing the absence of gloeocystidia but differs in having smaller basidiospores (5.2-6 x3.5-4.5 µm, measured from the type by the authors, Zhang et al. 2023).  Scytinostroma renisporumis similar to  S. subrenisporumby sharing ellipsoid to reniform basidiospores but differs by having cylindrical, subclavate or fusoid gloeocystidia and a distribution in Cote d'Ivoire, western Africa ( Boidin and Lanquetin 1987). 2017-07-11 China Libo County Maolan Nature Reserve 1 Guizhou Province holotype 2013-08-08 He China Qimen County Guniujiang Nature Reserve 1 Anhui Province 2018-10-03 He China Wuyishan County Wuyishan Nature Reserve 1 Fujian Province 2017-07-10 He China Huanjiang County Mulun National Nature Reserve Autonomous Region 1 Guangxi 2016-06-15 He China Libo County Maolan Nature Reserve 1 Guizhou Province 2018-08-03 He China Guzhang County Gaowangjie National Nature Reserve 1 Hunan Province 2016-08-09 2016-08-14 2016-08-09 He, Liana China Ji'an County Lianping County Jinggangshan Scenic Spot 1 Jiangxi Province