Amauroderma albostipitatum Gomes-Silva, Ryvarden & Gibertoni, 2015

Gomes-Silva, Allyne C., De Lima-Júnior, Nelson C., Malosso, Elaine, Ryvarden, Leif & Gibertoni, Tatiana B., 2015, Delimitation of taxa in Amauroderma (Ganodermataceae, Polyporales) based in morphology and molecular phylogeny of Brazilian specimens, Phytotaxa 227 (3), pp. 201-228 : 206-208

Amauroderma albostipitatum Gomes-Silva, Ryvarden & Gibertoni , sp. nov., Fig. 3

MycoBank: MB 811026

Amauroderma albostipitatum is above all distinguished by its whitish stipe and subglobose, 10–12 × 8–9 μm, basidiospores.

Holotype:— BRAZIL. Rondônia: Porto Velho, Fazenda Mucuim , on soil, July 2007, A.C. Gomes-Silva 102 (Holotype: URM 83242, isotype O).

Etymology:—album (Latin) = white; stipes (Latin) = foot; referring to the white stipe.

Basidioma annual, solitary, centrally stipitate. Pileus single, circular, applanate, 3.5–7.5 cm wide, 3–7 cm high, 0.5– 0.11 mm thick, hard when dry. Stipe cylindrical, central, solid, 7–8 cm long, 0.2– 0.12 mm diam., whitish (White 84), dull, glabrous to slightly velutinate, with thin cuticle, context of the stipe homogeneous, spongy, brown (Snuff brown 17). Abhymenial surface dull, glabrous to slightly velutinate, concentrically zonate, radially sulcate when dry, brown (Cigar brown 16, Snuff brown 17, Clay buff 32) when dry, occasionally with thin black cuticle. Margin entire, acute to slightly obtuse and wavy, concolorous to the abhymenial surface. Hymenial surface brown (Cigar brown 16, Snuff brown 17), poroid, pores circular, 4–5(–6) per mm, dissepiments entire, thin. Context homogeneous, spongy, 0.2–0.5 mm thick, brown (Cigar brown 16). Tubes concolorous to the hymenial surface, 0.3–0.6 mm deep. Hyphal system dimitic; generative hyphae hyaline to pale brown, clamped, thin-walled, 2–3.5 μm diam.; skeletal pale brown to brown, thick-walled to solid, arboriform, 3–5 μm diam., IKI- to slightly IKI+. Hyphal pegs absent. Basidia not observed. Basidiospores subglobose, yellow in KOH, thick-walled, finely ornamented, usually guttulate, 10–12 × 8–9 μm, IKIto rarely weakly IKI+.

Substrate: —on soil.

Distribution: —only known from the States of Rondônia and Roraima, in the Brazilian Amazonia.

Specimens examined: — BRAZIL. Rondônia: Porto Velho, Fazenda Mucuim, July 2007, A.C. Gomes-Silva w/n (URM 79468), A.C. Gomes-Silva 97 (URM 83243), Estação Ecológica de Cuniã, January 2009, A.C. Gomes-Silva 392 (URM 83244), August 2010, A.C. Gomes-Silva et al. 3049 (URM 83401), February 2011, A.C. Gomes-Silva et al. 2187 (URM 83245). Roraima: Boa Vista, Estrada Boa Vista-Venezuela, December 1977, I. Araújo et al. 755 [INPA 78474, as A. praetervisum (Pat.) Torrend (1920: 131) ].

Remarks:— Amauroderma albostipitatum is characterised by the brownish, zonate pileus; brown, small pores; whitish stipe and subglobose basidiospores. It might remind one of A. schomburgkii (Mont. & Berk.) Torrend (1920: 140) , but its basidiospores are globose and smaller (7–10 μm). Besides, the whitish stipe separates A. albostipitatum from the other species in the genus ( Ryvarden & Johansen 1980, Furtado 1981, Corner 1983, Ryvarden 2004a).

Figures

FIGURE 3. Amauroderma albostipitatum (URM 83242). A. Abhymenial surface. B. Hymenial surface. C. Basidiospores in KOH. D. Basidiospores in Melzer’s reagent. Scale: A–B = 1 cm; C, D = 10 μm. Photos: A.C. Gomes-Silva.