Gerronema confusum L. Fan & T.Y. Zhao, 2022

Zhao, Tao-Yu & Fan, Li, 2022, Gerronema confusum (Porotheleaceae), a new species from North China, Phytotaxa 550 (2), pp. 186-194 : 190-191

Gerronema confusum L. Fan & T.Y. Zhao sp. nov. ( Figs. 2 , 3 )

MycoBank:— MB841245

Diagnosis:— Gerronema confusum is similar to G. atrialbum and G. wildpretii in the appearance of basidiomata, however it can be distinguished from G. wildpretii in having larger basidiospores (7.5–12.5 × 5–10 μm) and the absence of clamp connections in all tissues, while from G. atrialbum in having shorter stipe (5–7 cm long) and abundant cheilocystidia. ITS-phylogeny supported G. confusum as a distinct species.

Etymology:—‘ confusum’, refers to its confusingly similar macro-morphology with G. wildpretii .

Holotype:— CHINA. Shanxi Province, Yuncheng City , Xia County, 35°0ʹ24ʺN, 111°31ʹ24ʺE, elev. 1020 m, 06 October 2020, Hao-Yu Fu, MNM101 ( BJTC FM1592 ).

Description: —Basidiomata omphalinoid, medium-sized. Pileus 55–65 mm broad, sometimes umbilicate, but predominantly infundibuliform to deeply infundibuliform; ground color gray white (#c0c0c0), covered with adpressed grayish brown (#7d371f) to brown (#52361b) fibrils and dark brown granulose (#3f2915) all over; margin almost straight to rather reflexed, undulate, with some white split. Lamellae decurrent, white (#d8eaf3), 3.5–4.5 mm broad, with lamelluale of 2–3 tiers, sometimes with the cross veins, edge entire, concolorous. Stipe 55–70 × 9–14 mm, cylindrical, equal or slightly broader towards the base, hollow; surface gray white to concolorous with the pileus, granulose toward apex, granulose dark brown (#3f2915). Context thin, white (#aac0da). Odour and taste indistinct.

Basidiospores 7.5–12.5 × 5–10 μm; Q(L/I) = 1–2(Qm = 1.47)(n = 60), ellipsoid to subglobose, thin-walled, smooth, inamyloid, hyaline, with a prominent apiculus, often with a large oil drop at the centre. Basidia 37.5–62.5 × 5–7.5 μm, clavate, sometimes fusiform, thin-walled, 1–2-spored; sterigmata up to 10 μm long. Cheilocystidia abundant, 42.5–62.5 × 5–12.5 μm, hyaline, thin-walled, subcylindrical to cylindrical. Pleurocystidia absent. Pileipellis a cutis disrupted by clusters of erect or semi-erect pileocystidia; hyphae hyaline or often with a light brown plasmatic pigment, thin-walled, with slightly swollen terminal elements. Pileocystidia 62.5–85 × 7.5–10 μm, flexuose, clavate or subclavate, with a light brown plasmatic pigment, thin-walled. Stipitipellis a cutis disrupted by caulocystidia and occasional ascending or erect hyphae with inflated terminal hyphae, hyaline or with a light brown plasmatic pigment. Caulocystidia 42.5–62.5 × 5–8.75 μm, with a light brown plasmatic pigment, cylindrical, fusoid, clavate or sometimes irregular in shape, thin-walled. Clamp connections absent.

Habitat:—Solitary, growing on buried wood in the broad-leaved forests dominated by Quercus sp.

Known distribution: — Shanxi, CHINA

Additional specimens examined: — CHINA. Shanxi Province, Yuncheng City , Xia County, 35°4ʹ46ʺN, 111°23ʹ43ʺE, elev. 1000 m, 04 October 2020, Ning Mao, MNM039 ( BJTC FM1624 ) .

Figures

FIGURE 2. Basidiomata of Gerronema confusum. Scale bars: a, b = 10 mm. Photos by: Li Fan and N. Mao.

FIGURE 3. Microscopic features of Gerronema confusum. a. Basidiospores. b. Basidia. c. Cheilocystidia. d. Caulocystidia. e. Pileipellis and pileocystidia. Scale bars: a, b, c = 5 μm; d = 10 μm; e = 100 μm. Photos by: Tao-Yu Zhao.