Crepidotus ulmicola T. Bau &amp; Y. P. Ge 2022, sp. nov.
Creators: name: Zhang, Peng
name: Ge, Yupeng
name: Bau, Tolgor
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Fungi
Basidiomycota
Agaricomycetes
Agaricales
Inocybaceae
Crepidotus
Crepidotus ulmicola

description: <i>Crepidotus ulmicola</i> T. Bau &amp; Y.P. Ge <i>sp. nov.</i> Figs. 3c, 3d, 5, 6 MycoBank MB837627 Diagnosis:—Pileus minute, white, tomentose,with a very small stipe visible when mature,lamellae distant, basidiospores broadly ellipsoid to ellipsoid, weakly rugulose, cheilocystidia lageniform, whip-like to slightly flexuous, pileipellis a trichoderm. Etymology:—The epithet refers to its habitat on and colonization of species of <i>Ulmus</i>. Type:— CHINA. Inner Mongolia Autonomous Region: Tumuji National Nature Reserve, Jalaid Banner, Hinggan League, elev. 137 m, 46°27′ N, 123°01′ E, 26 July 2015, <i>Tolgor Bau &amp; Yupeng Ge</i>, HMJAU37011 (Holotype!), GenBank no. KX456184 (ITS). Description:— <i>Pileus</i> (2–) 3–5 mm, in young stage angulate to round flabelliform, more or less spheroidal, white (1A1), distinctly radial-silky, becoming flabelliform, semicircular to subcircular, convex, whitish to light orangeyellow (5A2–5B2), tomentose, margin slightly inflexed, occasionally darker to honey yellow (4C6–4D6) or maize yellow (4A5–4B4), not hygrophanous, without striate edge when mature, attached laterally to dorsally. <i>Lamellae</i> 1–2 mm long, 0.5 mm broad, distant, <i>L</i> = 4–7, <i>l</i> = 2–4, white (1A1) when young, later light yellow (1A4) to yellow (3A5– 3B6), becoming rust brown when mature, subventricose to arcuate, adnexed to decurrent. <i>Stipe</i> 0.5–1.0 × 0.2–0.5 mm, light yellow (1A4–1A5), mostly curved, visible when mature (under stereomicroscope). <i>Context</i> white (1A1), very thin. <i>Odor</i> and <i>taste</i> nondistinctive. <i>Spore print</i> light brown (5D7). <i>Basidiospores</i> (6.9–)7.5–8.7 × (4.9–)5.6–6.7 μm, <i>Q</i> = 1.20–1.46, broadly ellipsoid to ellipsoid, slightly inequilateral in side view, yellow to light brown, almost smooth under immersion oil, weakly rugulose or vermiculate under SEM. Basidia 27–31.8 × (4.1–)6.3–10.8 μm, clavate, (2–)4-spored, thin-walled, hyaline, clamped. <i>Pleurocystidia</i> absent. <i>Cheilocystidia</i> 29–42(–53) × (3–)5–8(–10) μm, lageniform, whip-like to slightly flexuous, occasionally clavate, not septate at apex, thicker in the lower portion, hyaline, thin-walled, clamped. <i>Pileipellis</i> a trichoderm, composed of loosely interwoven hyphae. <i>Clamp connections</i> present in all tissues. Habitat:—Scattered on fissures in the bark of <i>Ulmus</i> trees. Known distribution:— China. Additional material examined:— CHINA. Jilin Province: Taohaotai Town, Qian Gorlos Mongol Autonomous County, Songyuan City, 162 m, 44°92′ N, 124°73′ E, 1 August 2015, <i>Tolgor Bau &amp; Yupeng Ge</i>, HMJAU37017!. <b>Notes:</b> According to the classification proposed by Consiglio and Setti (2008), <i>C. ulmicola</i> should be assigned to series <i>Dochmiopus</i> Consiglio &amp; Setti, section <i>Dochmiopus</i>, <i>Crepidotus</i> subgen. <i>Dochmiopus</i>. The tiny white basidiomes, tomentose pileus, and weakly rugulose basidiospores are the most distinctive features for distinguishing <i>C. ulmicola</i> from other <i>Crepidotus</i> species. Only a few <i>Crepidotus</i> species produce a basidiome similar in size to that of <i>C. ulmicola</i>, whose pileus is less than 10 mm in diameter. Hesler &amp; Smith (1965) assigned most species with a pileus not exceeding 10 mm in diameter to <i>Crepidotus</i> subgen. <i>Sphaerula</i> Hesler &amp; A.H. Sm. sect. <i>Sphaerula</i> Hesler &amp; A.H. Sm. or subsect. <i>Colorantes</i> Hesler &amp; A.H. Sm.; however, all such species are distinct from <i>C. ulmicola</i> on account of the honey-yellow to brownish or pale tawny pileus. In subsect. <i>Colorantes</i>, <i>C. albidus</i> Ellis &amp; Everhart (1894: 322) and <i>C. amarus</i> Murrill (1943: 430) have the greatest morphological resemblance to <i>C. ulmicola</i>, but they differ in basidiospore size. Krisai-Greilhuber <i>et al.</i> (2002) described <i>C. albidus</i> as possessing 5.9–6.9 × 4.7–5.6 μm basidiospores and occasionally clamps. The basidiospores of <i>C. albidus</i> are distinctly shorter than those of <i>C. ulmicola</i>. <i>Crepidotus amarus</i> differs from <i>C. ulmicola</i> in possessing clavate to cylindrical cheilocystidia, which are lageniform in <i>C. ulmicola</i> (Hesler &amp; Smith 1965). In our BLASTn search, the closest match to the ITS sequence (KX456184) of <i>C. ulmicola</i> was <i>C. occidentalis</i> (OK376745), with 95% sequence similarity, which is consistent with the results of the phylogenetic analysis. <i>Crepidotus occidentalis</i> is similar to <i>C. ulmicola</i> in basidiospore size but differs in possessing clavate cheilocystidia and a much larger pileus (Hesler &amp; Smith 1965).
description: Published as part of <i>Zhang, Peng, Ge, Yupeng &amp; Bau, Tolgor, 2022, Two new species of Crepidotus (Crepidotaceae) from China, pp. 22-34 in Phytotaxa 552 (1)</i> on pages 28-30, DOI: 10.11646/phytotaxa.552.1.2, http://zenodo.org/record/6673167
description: {"references": ["Consiglio, G. &amp; Setti, L. (2008) Il genere Crepidotus in Europa. Associazione Micologica Bresadola, Trento, Italy, 344 pp.", "Hesler, L. R. &amp; Smith, A. H. (1965) North American Species of Crepidotus. Hafner Publishing Company, New York, London, 168 pp.", "Ellis, J. B. &amp; Everhart, B. M. (1894) New Species of Fungi from Various Localities. Proceedings of the Academy of Natural Sciences of Philadelphia 46: 322 - 386.", "Murrill, W. A. (1943) Some Southern novelties. Mycologia 35: 422 - 433. https: // doi. org / 10.1080 / 00275514.1943.12017497", "Krisai-Greilhuber, I., Senn-Irlet, B. &amp; Voglmayr, H. (2002) Notes on Crepidotus from Mexico and the South-Eastern USA. Persoonia 17: 515 - 539. https: // doi. org / 10.1046 / j. 1439 - 0507.2002.00742. x"]}