Clitocella borealichinensis L. Fan & N. Mao, 2022

Mao, Ning, Lv, Jing-Chong, Xu, Yu-Yan, Zhao, Tao-Yu & Fan, Li, 2022, Two new Clitocella species from North China revealed by phylogenetic analyses and morphological characters, MycoKeys 88, pp. 151-170 : 151

Clitocella borealichinensis L. Fan & N. Mao sp. nov.

Figs 3a , 4 , 6a, b

Etymology.

borealichinensis, referring to north China as the place of origin.

Holotype.

China. Shanxi Province, Qinshui County, Lishan Mountain, 35°36.49'N, 112°11.7'E, alt. 1150m, 26 July 2021, on the ground in broad-leaved forest dominated by Quercus sp., N. Mao MNM340 (BJTC FM1781).

Diagnosis.

Clitocella borealichinensis is characterized by its clitocyboid basidiomata, globose to subglobose, occasionally broadly ellipsoid basidiospores, the absence of hymenial cystidia and clamp connection, and usually growing in broad-leaved forests. It is most similar to C. orientalis but differs from it by the slightly smaller basidiospores, non-gelatinized hyphae of pileipellis and stipitipellis with pale brown to brown intracellular or parietal pigment.

Description.

Basidiomata clitocyboid, small to medium-sized. Pileus 13-50 mm wide, low convex to plane convex when young, then slightly depressed at center; surface smooth, grayish white (#f2f2f2) to pale white (#ffffff), yellowish white (#ffcd9a); margin incurved, non-striate; context thin pale white, 1.0-1.2 mm thick. Lamellae decurrent, grayish white (#f2f2f2), pale yellow (#fff3e7), crowded, edges smooth, thin and fragile, lamellulae numerous and concolorous with lamellae. Stipe 20-32 × 2-8 mm, central to eccentric, occasionally lateral, cylindrical to subcylindrical, equal or sometimes slightly tapering at base, pale white (#ffffff), smooth or tomentose, usually with white rhizomorphs. Odor unrecorded. Taste not recorded. Chemical color reaction: not reacting with KOH 3% at pileus of dried specimens.

Basidiospores [60/2/2] (3.8-)4-5(-5.5) × 3.8-4.5 μm, Lm × Wm = 4.61 ( ± 0.42) × 4.06 ( ± 0.18), Q = 0.95-1.25 (Qav = 1.13 ± 0.10), hyaline, globose to subglobose, occasionally broadly ellipsoid in profile view, slightly angled in polar or face view with obscure minute pustules or bumps. Basidia 17-25 × 5-6(-7) μm, clavate, hyaline, four spored, rarely two spored; sterigmata 2-4 μm long. Lamellar trama more or less regular, composed of 3-8 μm wide hyaline hyphae, subhymenium consisting of filamentous hyphal segments. Lamellae edges fertile. Pleurocystidia and cheilocystidia absent. Pileipellis a cutis composed of more or less radially, loosely arranged, non-gelatinized, smooth, cylindrical hyphae, 2-6 μm wide and with pale brown to brown intracellular or parietal pigment; terminal hyphae subcylindric, narrowly clavate, occasionally irregular, 3-5 μm wide; subcutis made up of subparallel, compactly arranged, thin-walled, hyaline, smooth, cylindrical hyphae, 3-6 μm wide; pileal trama composed of interwoven, cylindrical hyphae, 2.5-10 μm wide. Stipitipellis a cutis composed of parallel, compactly arranged, thin-walled, non-gelatinized, hyaline hyphae, 2.5-6 μm wide. Stipititrama composed of interwoven, hyaline, cylindrical hyphae, 3-10 μm wide. Caulocystidia absent. Clamp connections absent.

Habit.

Scattered or in groups on soil in broad-leaved ( Quercus ) forest, Shanxi province, China.

Additional specimens examined.

China. Shanxi province, Xia County, alt. 970m, 7 October 2020, N. Mao MNM172 (BJTC FM1618) .

Note.

Clitocella borealichinensis is easily confused with C. orientalis , C. obscura ( Pilát) Vizzini et al. and C. pallescens Silva-Filho & Cortez in morphology because they are all have white to grayish white pileus and decurrent lamellae. However, C. orientalis differs from C. borealichinensis by its viscid pileus and stipe when wet, gelatinized pileipellis and stipitipellis, and slightly larger basidiospores of (4-)4.5-6 × 4-5 μm ( Jian et al. 2020). Clitocella obscura produce a distinctly reddish reaction when 3% KOH is placed on the pileus surface ( Baroni 1981; as Rhodocybe ) while C. borealichinensis has not that kind of reaction. Clitocella pallescens differs C. borealichinensis by its pale grey to yellowish white stipe ( Silva-Filho et al. 2018; Jian et al. 2020).

Clitocella mundula and C. popinalis clustered with C. borealichinensis in our multilocus phylogeny (Fig. 1 ), indicating they are phylogenetically closely related to each other. Morphologically, C. mundula differs from C. borealichinensis by its yellowish gray or brown to dark smoke gray pileus and slightly larger basidiospores of (4-)4.5-6(-6.5) × 4-5 μm ( Jian et al. 2020), C. popinalis by its brown to grayish brown pileus, bigger basidiospores of 5.5-7-5-5.5 μm, and its pileus surface produces a reddish reaction in 3% KOH ( Baroni 1981; as Rhodocybe ). Moreover, DNA analysis also revealed that C. borealichinensis shared less than 91.10% similarity in tef1 sequence with C. mundula and 91.20% similarity with C. popinalis , supporting their separation.

Figures

Figure 1. Phylogeny derived from Maximum Likelihood analysis of the combined nrLSU- rpb 2 - tef 1 - atp 6 dataset of Clitocella and related genera in the family Entolomataceae. Clitopilopsis albida was employed to root the tree as an outgroup. Numbers representing likelihood bootstrap support (BS ≥ 70 %, left) and significant Bayesian posterior probability (BPP ≥ 0.95, right) are indicated above the nodes. New sequences are highlighted in bold.

Figure 3. Basidiomata of Clitocella a Clitocella borealichinensis (BJTC FM 1781, holotype) b-d Clitocella colorata (b BJTC FM 1593 c BJTC FM 1952 d BJTC FM 1891, holotype) Scale bars: 10 mm (a-d). Photos by JingZhong Cao

Figure 4. Microscopy of Clitocella borealichinensis a basidiospores b basidia c pileipellis. Scale bars: 5 μm (a); 10 μm (b, c). Drawings by Ning Mao.

Figure 6. Basidiospores of species in Clitocella. Clitocella revealed by SEM a, b Clitocella borealichinensis c, d Clitocella colorata Scale bars: 3 μm (a, b); 5 μm (c, d). Photos by Li Fan.