Leucoinocybe subglobispora Q.Na & Y.P.Ge, 2024

Na, Qin, Zeng, Hui, Hu, Yaping, Ding, Hui, Ke, Binrong, Zeng, Zhiheng, Liu, Changjing, Cheng, Xianhao & Ge, Yupeng, 2024, Morphological and phylogenetic analyses reveal five new species of Porotheleaceae (Agaricales, Basidiomycota) from China, MycoKeys 105, pp. 49-95 : 49

Leucoinocybe subglobispora Q.Na & Y.P.Ge sp. nov.

Figs 8 , 9 , 10

Diagnosis.

Pileus dark brown. Basidiospores subglobose to broadly ellipsoid. Pileocystidia and caulocystidia thick-walled. Differs from L. lishuiensis in having broader basidiospores.

Holotype.

China. Zhejiang Province: Tianmu Mountain, Hangzhou City, 1 Aug 2021, Qin Na, Yupeng Ge, Zewei Liu and Yulan Sun, FFAAS1034 (collection number MY0444).

Etymology.

Name refers to the subglobose to broadly ellipsoid basidiospores.

Description.

Pileus 2.5-8.0 mm in diameter, hemispherical or campanulate when young, becoming campanulate with age, umbilicate at the centre, sulcate, finely granulose all over, Dark Livid Brown (XXXIX1′′′k), Benzo Brown (XLVI13′′′′i) to Fuscous (XLVI13′′′′k) at the centre, Pale Smoke Grey (XLVI21′′′′f) in the margin, uplifted or recurved at the margin and sometimes rimose in age, dry. Context white, thin, fragile. Lamellae adnexed to slightly subdecurrent, white, with 1-2 tiers of lamellulae, edges concolorous with the face. Stipe 9.5-14.0 × 1.0-1.5 mm, equal or slightly broadened at the base, hollow, fragile, white, sometimes inconspicuous Pale Olive-Buff (XL21′′′d) at the base, densely pruinose, but sparsely with age, base covered with small white fibrils. Odour and taste indistinctive.

Basidiospores (60/3/2) (5.6) 5.8-6.4-7.1 (7.5) × (4.8) 5.0-5.6-6.5 (6.8) μm [Q = 1.06-1.27, Q = 1.16 ± 0.054] [holotype (40/2/1) (5.7) 5.9-6.5-7.2 (7.5) × (4.9) 5.0-5.5-6.5 (6.8) μm, Q = 1.07-1.27, Q = 1.18 ± 0.052], subglobose to broadly ellipsoid, hyaline in 5% KOH, smooth, thin-walled, guttulate, amyloid. Basidia 28-37 × 7-9 μm, 4-spored, clavate, sterigmata 1.4-2.7 × 0.8-1.7 μm. Cheilocystidia 28-62 × 9-15 μm, distinct, flexuose, narrowly utriform, fusoid or lageniform, subcapitate, thin-walled, hyaline. Pleurocystidia absent. Lamellae trama subregular; hyphae 2-6 μm wide, thin-walled, hyaline, amyloid. Pileipellis hyphae 2-8 μm wide, smooth; pileocystidia 62-116 × 10-19 μm, lageniform, subulate, apically obtuse, distinctly 0.8-1.8 μm thick-walled, with a thin-walled base, hyaline, smooth. Stipitipellis a cutis made up of 3-9 μm wide hyphae, smooth, thin-walled; caulocystidia 34-62 × 5-10 μm, subulate, fusoid, lageniform, sometimes clavate, always thick-walled in the middle part and with a thin-walled base, smooth, transparent. Clamps present in all tissues.

Habit and habitat.

Solitary or scattered on rotten wood or branches in Acer , Armeniaca , Cercidiphyllum , Emmenopterys and Picea mixed forests.

Known distribution.

Zhejiang Province, China.

Additional material examined.

China. Zhejiang Province: Baiyun National Forest Park, Liandu District , Lishui City , 2 Aug 2021, Qin Na, Yupeng Ge, Zewei Liu, Yaping Hu and Hui Ding, FFAAS1035 (collection number MY0475) .

Notes.

Leucoinocybe subglobispora is considered to be a distinct species of Leucoinocybe on account of its subdecurrent lamellae, subglobose to broadly ellipsoid basidiospores, thick-walled pileocystidia and caulocystidia and saprophytic habitat. Leucoinocybe lenta , the type species of Leucoinocybe , also has a white stipe and lamellae, similarly-shaped cheilocystidia and thick-walled pileocystidia, but differs from the new species by the presence of a reddish-brown pileus with pinkish shades or pale pinkish-beige at the centre that fades to white towards the margin, larger basidiomata and ellipsoid basidiospores [(5.3)6.0-7.3(7.9) × (3.8)4.0-4.5(5.1) μm] ( Gröger 2006; Eyssartier and Roux 2011; Antonín et al. 2019; Kaygusuz et al. 2020). Leucoinocybe taniae (= Clitocybula flavoaurantia ) resembles L. subglobispora in having a brown pileus, white and decurrent lamellae and a white stipe with a brownish base, but differs in possessing the following features: a reddish-yellow pileus when old, larger and broadly amygdaliform spores (6.2-7.8 × 4.8-7.0 μm) and thin-walled pileocystidia and caulocystidia ( Vila 2002; Contu 2003; Malysheva and Morozova 2011; Antonín et al. 2019). Leucoinocybe sulcata , recently described as a new taxon from India, is easily distinguished from the new species by the presence of greyish-orange to brown basidiomata, a larger pileus (13-52 mm in diam.), broadly ellipsoid to subamygdaliform basidiospores (5.0-6.5 × 4.0-5.5 μm; Q = 1.1-1.5) and thin-walled caulocystidia and the absence of pileocystidia ( Latha et al. 2015). Leucoinocybe lishuiensis , reported as a new species from south-eastern China in our previous study, can be easily mistaken for L. subglobispora on account of having an identical habit and habitat, a small, pure-brown pileus, slightly decurrent lamellae, similarly-shaped cheilocystidia and thick-walled pileocystidia and caulocystidia; however, the narrowly ellipsoid basidiospores and smaller pileocystidia of L. lishuiensis can be used to distinguish this species from L. subglobispora ( Na et al. 2021). Another new combination of Leucoinocybe , L. auricoma (Har. Takah.) Matheny, originally named Mycena auricoma Har. Takah., is also comparable to the present species in having thick-walled pileocystidia and caulocystidia; however, L. auricoma has a yellowish-orange flocculent pileus and stipe, ovoid-ellipsoid to ellipsoid basidiospores (5-7 × 3-4 μm) and pileocystidia and caulocystidia with yellow contents ( Takahashi 1999; Matheny et al. 2020).

Figures

Figure 8. Basidiomata of Leucoinocybe subglobispora A-E collection FFAAS 1034, holotype F-G collection FFAAS 1035. Scale bars: 10 mm (A-G).

Figure 9. Morphological features of Leucoinocybe subglobispora (FFAAS 1034, holotype) A basidiomata B basidiospores C cheilocystidia D basidia E caulocystidia F pileocystidia. Scale bars: 5 mm (A); 10 μm (B-F).

Figure 10. Microscopic features of Leucoinocybe subglobispora (FFAAS 1034, holotype) A-E basidiospores F basidia G - J cheilocystidia K lamellar trama L pileipellis and pileocystidia M caulocystidia. Scale bars: 5 μm (A-E); 10 μm (F-M). Structures were stained with 1 % Congo Red aqueous solution before photographing.