Entoloma griseocarpum Xiao L. He & E. Horak

He, Xiao-Lan, Horak, Egon, Wang, Di, Peng, Wei-Hong & Gan, Bing-Cheng, 2018, Three new species of EntolomasubgenusPouzarella from China based on morphological and molecular data, MycoKeys 44, pp. 1-18 : 1

Entoloma griseocarpum Xiao L. He & E. Horak sp. nov. Figs 1c, d, 3

Diagnosis.

E. griseocarpum is characterised by the greyish-brown pileus, large basidiospores (12.5-15.5 × 7.5-9 µm) and broadly clavate, ovoid to lageniform cheilocystidia.

Type.

CHINA. TIBET: Linzhi, Lulang, 29°94'N, 94°79'E, elevation ca. 3800 m, 18 September 2014, He X.L. (SAAS 1328, holotype).

Etymology.

griseocarpum, refers to the greyish-brown coloured basidiomes.

Description.

Pileus 5-20 mm broad, hemispherical, convex, bluntly conic to broadly campanulate, dry, not hygrophanous, greyish-brown to brown (4D3-4E3), densely covered by suberect hispid or minutely squamulose overall, denser in centre; fibrils dark grey, pale grey brownish or concolorous with pileal surface (4D2-4D3), striate from entire margin to near centre. Lamellae sinuate with short decurrent tooth, ventricose, distant, moderately thick, up to 3 mm broad, with two tiers of lamellulae, dark grey to brownish-grey, with entire and concolorous edges. Stipe 20-50 × 0.7-1.5 mm, cylindrical, equal, dry, concolorous with pileus, densely covered with pale yellow brownish flocculose hairs, hollow, with a dirty yellowish to pale yellow brownish strigose base. Context thin, concolorous with pileus. Odour and taste not distinctive.

Basidiospores 12.5-15.5 (-17) × (6.5-) 7.5-9 (-9.5) µm (x = 13.8 ± 0.3 × 8.3 ± 0.3 µm), Q = 1.60-1.94 (Q = 1.71 ± 0.02), heterodiametric, strongly angled in profile and face view with 6-10 facets, appearing nodulose, pale yellow brownish, thick-walled. Basidia 35-55 × 11-13 (-15) µm, subclavate to clavate, 4-spored. Aborted basidia scattered in the hymenium, filled with dark brown amorphous cytoplasmic pigment. Lamellar trama dark brown, composed of parallel, cylindrical, heavily encrusted and thin-walled elements. Lamellar edges sterile. Cheilocystidia 23-50 × (10-) 12 20 µm, broadly clavate, ovoid to lageniform; with brownish, intracellular pigment, slightly thick-walled. Pileipellis a trichoderm composed of yellow brown, suberect and multiseptate hyphae, walls heavily encrusted with brown pigment; terminal cells 35-105 × 8-27 µm, cylindrical, subclavate or bullet-shaped, thin to moderately thick-walled; subpellis composed of cylindrical encrusted hyphae, up to 25 µm diam. Stipitipellis composed of yellow-brown encrusted hyphae; terminal cells 40-80 × 4-10 µm, slender cylindrical with obtuse apex, thin-walled, sparsely encrusted with pale yellowish-brown pigment. Oleiferous hyphae absent. Clamp connections absent.

Habitat.

Scattered on soil amongst decaying litter in mixed conifer-broadleaf forest dominated by Quercus , Betula , Rhododendron and Abies .

Additional collections examined.

CHINA. TIBET: Linzhi, Lulang, 29°94'N, 94°79'E, elevation ca. 3800 m, 18 September 2014, He X.L. (SAAS 1230, SAAS 1657, SAAS 1751, SAAS 1871). SICHUAN PROV.: Jiuzhaigou, 33°28'N, 103°59'E, elevation ca. 3000 m, 20 July 2013, He X.L. (SAAS 951).

Comments.

The greyish-brown pileus covered by suberect hispid or minutely squamulose, the brown external encrustations on pileipellis and stipitipellis and the cylindrical terminal cells of pileipellis and stipitipellis indicate E. griseocarpum belongs to the sect. Dysthales . It is very similar to E. albostrigosum (Largent & Abell-Davis) Blanco-Dios and E. lasium (Berk. & Broome) Noordel. & Co-David ( Largent et al. 2011). However, E. albostrigosum is distinguished by the white strigose base and E. lasium differs by the smaller basidiospores (8.9-14.5 × 5.1-8.7 μm, Largent et al. 2011). In addition, the two species are distant from E. griseocarpum following phylogenetic analysis. E. puertoricense Blanco-Dios (as P. caribaea T.J. Baroni & B. Ortiz in Baroni and Ortiz 2002) resembles E. griseocarpum by the brownish-grey coloured basidiomes but is separated by its broader basidiospores (12.5-16.5 × 8.3-11.3 μm, Q = 1.26-1.65, Baroni and Ortiz 2002). Moreover, E. puertoricense was discovered in a tropical habitat in Puerto Rico ( Baroni and Ortiz 2002). The similar E. japonicum (Hongo) Hongo, described from Japan, is also reminiscent of E. griseocarpum in the brownish pileus but is distinguished by the much larger basidiospores (15-18.5 × 9-10.5 μm, Hongo 1959). The well-known E. dysthales (Peck) Sacc. also differs by the larger basidiospores (14-20 × 7.5-10 µm, Mazzer 1976). E. fulvolanatum (Berk. & Broome) Blanco-Dios from Sri Lanka is not only separated by its type locality but also by the narrower basidiospores measuring 12-16 × 7-8 μm ( Mazzer 1976). Two species in subgen. Pouzarella , recently described from geographically neighbouring India, viz. E. peechiense K. N. A. Raj & Manim. and E. silvanum K. N. A. Raj & Manim., have somewhat similar basidiomes as compared to E. griseocarpum ; however, their ITS and LSU sequences are distinctly different ( Raj and Manimohan 2017). The third Indian species E. lomapadum Manim., Joseph & Leelav. is readily recognised by the much smaller basidiospores measuring 11-13 × 6-9 μm ( Manimohan et al. 1995). There were four other species in subgen. Pouzarella which showed some similarities to E. griseocarpum . E. fibrillosipes (Murrill) Noordel. & Co-David is distinguished by the much larger basidiospores (17-22 × 7.5-10 μm, Mazzer 1976). E. subdeceptivum Courtec. and E. rotula (Romagn.) Noordel. & Co-David are lignicolous ( Mazzer 1976). E. homomorphum (Romagn.) Singer differs by the larger basidiospores (15-19 × 9-11.5 μm, Mazzer 1976).