Pseudosperma arenarium Y.G. Fan, Fei Xu, Hai J. Li & Vauras, 2022

Yan, Ya-Ya, Zhang, Yi-Zhe, Vauras, Jukka, Zhao, Li-Na, Fan, Yu-Guang, Li, Hai-Jiao & Xu, Fei, 2022, Pseudosperma arenarium (Inocybaceae), a new poisonous species from Eurasia, based on morphological, ecological, molecular and biochemical evidence, MycoKeys 92, pp. 79-93 : 79

Pseudosperma arenarium Y.G. Fan, Fei Xu, Hai J. Li & Vauras sp. nov.

Figs 2 , 3

Etymology.

refers to its habitat of sandy soils.

Holotype.

China, Ningxia Hui Autonomous Region, Wuzhong, Yanchi County, Yanchi Railway Station, on sandy ground under Populus alba × P. berolinensis , 5 Oct 2020, NXYC20201005-01 (FCAS3571, holotype). GenBank accession nos.: ITS-OM304278, LSU-OM304287, rpb2 -OM421667.

Diagnosis.

Basidiomata robust, pileus beige, ivory white or yellowish; basidiospores> 13 μm, cylindrical to cylindrical-ellipsoid, cheilocystidia thin-walled. Occurs under artificial plantations of Populus alba × P. berolinensis or open seashore forest of Pinus sylvestris Linn. Differs from P. arenicola by longer basidiospores and phylogenetic distance.

Basidiomata.

medium-sized, robust. Pileus 35-65 mm in diameter, spherical to hemispherical when young, convex, dome-shaped to applanate when mature, not umbonate, margin inrolled at first, becoming depressed, straight, to uplifted or recurved in age; surface dry, glabrous to slightly fibrillose, occasionally rimulose to rimose at the margin, with distinct sandy remnants; yellowish (1A2) to ochraceous (1A4), paler outwards, ivory white (1B1) to greyish-white (1B2) when dried. Lamellae crowded, up to 8 mm in width, adnexed to sub-free, not equal, alternately distributed with three tiers of lamellula, initially pure white to creamy white (1A2), becoming yellowish (4A3), brownish (5B6) to cinnamon (5C8) with age, yellowish-brown (4B8) to dark brown (6C7) after drying, edge pinkish-white, fimbricate. Stipe 40-100 × 7-20 mm, solid, equal or slightly tapering downwards, sometimes swollen towards the base, but not marginate, longitudinally fibrillose with scattered squamules, white to ivory white (1B1-1B2) with pinkish tinge (11A3) when fresh, yellowish (5A4) to brownish (5B5) upon drying. Context solid, white and fleshy in pileus, 2-5 mm in thickness, fibrillose in the stipe, striate and shiny, white to somewhat pinkish (7A2). Odour fungoid or slightly spermatic.

Basidiospores.

[170/6/4] (13-)14-20(-21) × (6-)7-9.2(-11) μm, median 16.4 × 7.8 μm, Q = (1.6-)1.75-2.64(-2.95), Qm = 2.12 ± 0.27, yellow-brown, smooth, mostly cylindrical to cylindrical-ellipsoid, less often narrowly ellipsoid to nearly phaseoliform. Basidia 32-42 × 11-14 μm, clavate, usually narrower downwards, four-spored, sterigmata up to 10 μm long, translucent with oily inclusions, occasionally with yellowish pigments. Pleurocystidia absent. Lamellae edge sterile. Cheilocystidia 30-77 × 12-23 μm, thin-walled, colourless, broadly clavate or fusiform, rarely septate, translucent or occasionally with golden yellow inclusions, walls yellowish. Caulocystidia not observed. Hymenophoral trama nearly regularly arranged, composed of translucent and pale yellow, thin-walled hyphae up to 22 μm wide. Pileipellis a cutis, regularly arranged, orange-brown to brownish in 5% KOH, composed of cylindrical hyphae 4-15 μm in diameter; pileal trama made up of compact, parallel, hyaline hyphae, pale yellow in mass. Stipitipellis a cutis frequently disrupted by loose hyphal projections, hyphae thin-walled, colourless, 3-16 μm wide. Stipe trama regularly and densely arranged, yellowish in mass, hyphae thin-walled, colourless, 8-21 μm wide. Oleiferous hyphae 4-15 μm wide, present in pileus and stipe, bright yellow, smooth, often bent, occasionally branched or catenate. Clamp connections are common in all tissues.

Habitat.

individual or scattered on sandy and saline-alkali soil under artificial plantations of Populus alba × P. berolinensis in China and open seashore forest of Pinus sylvestris in Estonia. Fruiting in autumn, from late September to early October.

Known distribution.

China (Ningxia and Shaanxi), Estonia.

Additional materials examined.

China. Ningxia Hui Autonomous Region, Wuzhong, Yanchi Country , on sandy ground under Populus alba × P. berolinensis , 22 Sep 2021, NX20210922-57 (FCAS3572), GenBank accession nos.: ITS-OM304279, LSU-OM304288, rpb2 - OM421668 ; Shaanxi Province, Yulin, Dingbian Country, Yanchangbao Country , Xiliangwan Village , on sandy ground under Populus alba × P. berolinensis , 30 Sep 2021, SX20210930-65 (FCAS3573), GenBank accession nos.: ITS-OM304280, LSU-OM304289, rpb2 - OM421669 . Estonia. Saaremaa, Kaarma Municipality, Mändjala, open seashore forest with Pinus sylvestris Linn., on fine calcareous sand, 19 Sep 2008, Jukka Vauras 26578F (TUR-A182630), GenBank no.: ITS and LSU-FJ904154 .

Figures

Figure 2. Pseudosperma arenarium and its habitat a basidiospores b, c cheilocystidia d-h basidiomata. Scale bars: 10 μm (a-c); 10 mm (d-h). Photos by Xu Fei, Li Hai-Jiao & Zhao Li-Na.

Figure 3. Microfeatures of Pseudosperma arenarium (holotype) a basidiospores b basidia c cheilocystidia d pileipellis. Scale bars: 10 μm (a-d). Line drawings by Li Hai-Jiao.