Hymenochaete orientalis S.H. He

Nie, Ting, Tian, Yan, Liu, Shi-Liang, Yang, Jiao & He, Shuang-Hui, 2017, Species of Hymenochaete (Hymenochaetales, Basidiomycota) on bamboos from East Asia, with descriptions of two new species, MycoKeys 20, pp. 51-65 : 55-58

Hymenochaete orientalis S.H. He sp. nov. Figs 4, 5

Diagnosis.

This species is distinguished by lacking a hyphal layer and having relatively large, oblong-ellipsoid to cylindrical basidiospores.

Holotype.

CHINA. Taiwan: Nantou County, Ren’ai Township, Nandongyan Mountains, on fallen bamboo, 7 Dec 2016, He 4601 (holotype: BJFC; isotype: TNM).

Etymology.

" Orientalis " (Lat.) refers to the known distribution in East Asia.

Fruiting body.

Basidiomes annual, resupinate, effused, closely adnate, crustaceous to coriaceous, at first as small irregular patches, later confluent up to 20 cm long, up to 100 µm thick. Hymenophore smooth, brownish orange [7C(5-8)], light brown [7D (5-8)], brown [7E (5-8)] to reddish brown [8E (4-8)], not cracked; margin indeterminate, concolorous with hymenophore surface. Tissues darkening in KOH.

Microscopic structures.

Tomentum, cortex and hyphal layer absent. Hyphal system monomitic. Generative hyphae simple-septate, colorless to pale yellow, moderately thick-walled, frequently branched at right angles, densely interwoven, agglutinated, 2.5-4 µm in diam. Setae abundant, subulate, bearing an acute tip, yellowish to reddish brown, arranged in 1-3 overlapping rows, usually with a hyphal sheath and a basal hyphal node composed of densely interwoven hyphae, without encrustations or slightly encrusted with age, 70-120 × 7-10 µm, projecting out of the hymenium up to 85 µm. Basidia clavate to subcylindrical, usually with a constriction in the middle part, some with walls thickening towards the base, colorless, with 4 sterigmata and a basal simple septum, 15-23 × 4-5.5 µm; basidioles similar to basidia but smaller. Basidiospores oblong-ellipsoid to cylindrical, with a small apiculus, colorless, thin-walled, smooth, sometimes with one or two small guttulae, 6 –8(– 8.5) × 3 –3.8(– 4) µm, L = 6.7 µm, W = 3.3 µm, Q = 2-2.1 (n = 60/3).

Additional specimens examined

(paratypes: BJFC). CHINA. Guangxi Autonomous Region: Jinxiu County, Dayaoshan Nature Reserve, on fallen angiosperm twig, 25 Aug 2011, He 1000; Nanning, Damingshan Nature Reserve, on fallen angiosperm twig, 29 Aug 2011, He 1057; Qingxiushan Park, on fallen angiosperm twig, 15 Jul 2012, He 1230. Guangdong Province: Guangzhou, South China Botanical Garden, on fallen angiosperm twig, 5 Jul 2010, He 235; Heyuan County, Daguishan Forest Park, on fallen angiosperm twig, 18 Aug 2011, He 1212.

Remarks.

Hymenochaete orientalis belongs to sect. Gymnochaete G.A. Escobar ex J.C. Léger sensu Léger (1998), and is morphologically very similar to Hymenochaete longispora Parmasto. However, Hymenochaete longispora has hyphidia in hymenium and longer basidiospores, 8-10 µm according to Léger (1998). Hymenochaete cinnamomea (Pers.) Bres. also resembles Hymenochaete orientalis , but differs by the presence of a hyphal layer composed of loosely interwoven hyphae and smaller basidiospores, 5-6.5 × 2.5-3 µm according to Léger (1998). Hymenochaete minuscula G. Cunn. in sect. Gymnochaete can be distinguished from Hymenochaete orientalis by its smaller setae (40-56 × 5-6 µm) and basidiospores (4-5 × 1.8-2.2 µm) according to Léger (1998). In the phylogenetic tree, Hymenochaete orientalis formed a lineage close to Hymenochaete cinnamomea and Hymenochaete minuscula , but is distant from Hymenochaete longispora (Fig. 1).

Other specimens examined ( BJFC)

Hymenochaete innexa : CHINA. Taiwan: Nantou County, Xinyi Township, Xitou Research Center, on fallen bamboo, 11 Dec 2016, He 4640. Hymenochaete muroiana : CHINA. Xizang Autonomous Region: Linzhi County, Gadinggou Forest Park, on dead bamboo, 25 Sep 2010, He 405. Hunan Province: Dong’an County, Shunhuangshan Nature Reserve, on bamboo stump, 13 Jul 2015, He 2379. Hainan Province: Wuzhishan County, Wuzhishan Nature Reserve, on dead bamboo, 10 Jun 2016, He 3953. Guangdong Province: Zhaoqing County, Dinghushan Nature Reserve, on dead bamboo, 30 Jun 2010, He 172. Guangxi Autonomous Region: Jinxiu County, Dayaoshan Nature Reserve, 23 Aug 2011, He 947. Taiwan: Nantou County, Ren’ai Township, Nandongyan Mountains, on dead bamboo, 7 Dec 2016, He 4608. THAILAND. Chiang Rai Province: Campus of Mae Fah Luang University, on dead bamboo, 21 Jul 2016, He 4044. Hymenochaete rhabarbarina : CHINA. Taiwan: Nantou County, Xinyi Township, Xitou Research Center, on fallen bamboo, 11 Dec 2016, He 4636. Hymenochaete tropica : CHINA. Hainan Province: Wuzhishan County, Wuzhishan Nature Reserve, on fallen bamboo, 10 Jun 2016, He 3959.