Hypomyces sichuanensis Jing Z. Sun, 2021

Gu, Xin, Fu, Rong, Wang, Rui & Sun, Jing-Zu, 2021, Two new Hypomyces associated with boletoid fungi in China, Phytotaxa 516 (1), pp. 28-42 : 37-39

Hypomyces sichuanensis Jing Z. Sun , sp. nov. FIGURE 3

Index Fungorum number: IF558006

Etymology: — The specific epithet refers to the type locality of the fungus.

Type:— CHINA, Sichuan Province, Yancheng city (27°39′37″N, 101°14′11″E), from a fruiting body of Boletus sp. 8 August 2018 ; Fu Rong & Liu Xing-Zhong ( HMAS 291302 , holotype), ex - type living culture CGMCC 3.20159 .

Fungicolous, growing on a fruiting body of Boletaceae sp. Asexual morph: Hyphomycetous. Mycelium forms a loosely attached layer on the fruiting body of the host ( FIGURE 3a ). On PDA medium, colony tomentose to pubescent, white at the beginning, then becoming yellow ( FIGURE 3b, c ). Mycelium superficial, developing as floccose masses of septate, branched, smooth and hyaline hyphae bearing robust conidiophores with golden yellow spore masses ( FIGURE 3b ). Conidiophores hyaline, erect, flexuous, septate, smooth. With two types of conidiogenous cells phialidic and aleuriogenic ( FIGURE 3d–i ). Type A: Phialides in 2–3 verticels, or solitary, 65–180 × 2–3 μm (= 115 × 2.5 μm, n = 30), attenuating to 1.0–2.0 μm at their apices ( FIGURE 3d–f j ). Phialoconidia acrogenous, hyaline, thin - walled, ellipsoid to clavate, aseptate, 11.5–18 × 3–6 μm (= 14.5 × 5 μm, n = 50) ( FIGURE 3l ). Type B: Aleuriogenic discrete, on short or long side branches ( FIGURE 3d, h, i ). Aleurioconidia hyaline at the beginning, becoming golden yellow when mature, subglobose to globose, thick - walled, aseptate, with angular tubercles on surface, 8.5–15.5 × 8–15 μm (12.5 × 12 μm, n = 50) ( FIGURE 3h, i, k ). Tubercles densely, cylindrical, 1–2 μm, often with apical depression ( FIGURE 3k ). Sexual morph: Undetermined.

Other material examined:— CHINA, Sichuan Province, Yancheng city (27°39′36″N, 101°14′40″E), from a fruiting body of Boletales sp. 8 Aug 2018; Fu Rong ( YY30-1 ), living culture CGMCC 3.20160 .

Notes:—The new species grows on fruiting bodies of Boletaceae sp. containing only the asexual state. Among the known Boleticolous species of Hypomyces , H. sichuanensis is morphologically similar to H. chrysospermus Tul. & C. Tul. , H. microspermus Rogerson & Samuels , and Sepedonium laevigatum Sahr et Ammer in forming poorly developed verticills conidiophores and the shape and size of aleurioconidia ( Rogerson & Samuels 1989). Compared with H. chrysospermus , H. microspermus , and S. laevigatum , aleuriospores and phialoconidia of H. sichuanensis averaged somewhat smaller than those of H. chrysospermus (14–21 μm for aleuriospores, and 5–27 × 3–11 μm for phialoconidia) and S. laevigatum (14–19 μm for Aleuriospores, and 8–24 × 3.5–9.5 μm for phialoconidia) but larger than that of H. microspermus (9–15 μm for Aleuriospores, and 6.4–11.7 × 4–6.5 μm for phialoconidia) ( Sahr et al. 1999, TABLE 2). Additionally, H. sichuanensis also differs from S. laevigatum by no yellow discoloration of medium ( Sahr et al. 1999).

Figures

FIGURE 3. Hypomyces sichuanensis (CGMCC 3.20159). a Yellow colony on a fruiting body of Boletus sp. b, c Forward and reverse of a colony on PDA. d, e, g Conidiophores. f Phialides. h, i Aleurioconidia on short side branches. k Aleurioconidia. j Conidiogeous cell. l Phialoconidia. Scale bars: d–g = 50 μm, h–j = 20 μm, k, l = 10 μm.