Neotropicomus australis
Neotropicomus australis A.C. Magnago 2022, in Magnago, et al., Mycologia 114, 607-625 (2022)
Etymology: australis (Latin), referring to the type locality in southern Brazil.
Diagnosis: Differs from Neotropicomus parvogracilis by its finely pruinose to subscabrous upper stipe, black NH4OH reaction on the pileus, and presence of cheilocystidia.
Pileus 16–36 mm broad, convex to plano-convex with age; surface smooth to rugulose, slightly viscid when wet, reddish brown (OAC 636, OAC 734), lighter concolorous to pinkish brown (OAC 667) toward the margin; margin straight. Hymenophore adnate, depressed and sublamellate around the stipe, light greenish yellow (OAC 849) to yellow (OAC 856); tubes 3–4 mm long centrally; pores mostly 1 mm wide, angular, unchanging under pressure. Stipe 18–36 × 4– 7 mm, central, equal, upper half finely pruinose to subscabrous; scales reddish brown (OAC 733) over a cream (OAC 857) ground; lower half increasingly glabrous and light brown (OAC 750); basal mycelium white, downy. Context pale white (OAC 816), unchanging on exposure. Odor and taste not obtained. Macrochemical reactions: 10% NH4OH black on pileus surface and pinkish on stipe surface; 3% KOH reddish on pore surface. Basidiospores olivaceous in fresh deposit, 12–14 × 4– 5 μm (Qm = 2.58, n = 40, s = 8), subfusoid to fusoid, golden yellow in H2O, paler in 3% KOH, smooth, thin-walled, inamyloid. Basidia 29–38 × 10–13 μm, clavate, hyaline with many oil droplets, 4-sterigmate; sterigmata 3–4 μm long. Pleurocystidia scattered, 48–72 × 8–11 μm, narrowly fusoid to ventricose with a long neck, hyaline, inamyloid. Cheilocystidia 19–33 × 10–13 μm, pyriform, broadly clavate or ventricose, hyaline, inamyloid. Hymenophoral trama phylloporoid, hyaline; mediostratum poorly differentiated; individual hyphae 4–7 μm wide; lateral stratum not gelatinizing, of densely arranged, parallel to slightly divergent hyphae, these 5–12 μm wide. Pileipellis a trichoderm of anticlinal, densely packed chains of subglobose cells and polymorphic terminal elements, these globose to broadly clavate, often with subacute papillate apex, 17–35 × 11–18 μm, hyaline, inamyloid. Pileus trama interwoven; individual hyphae 4–19 μm wide, hyaline. Stipitipellis a palisade of erect clusters of hyaline caulocystidia, these 16–34 × 9– 13 μm, subglobose, pyriform, clavate or fusiform. Stipe trama of compact, longitudinally oriented hyphae, these 4–12 μm wide. Clamp connections absent.
Index Fungorum Number: IF836728
Figure 1. Neotropicomus australis. A–G. ACM 1000, holotype. H. ACM 1152. A. Basidiospores. B. Basidia. C. Pleurocystidia.D. Cheilocystidia. E. Pileipellis terminal elements. F. Stipitipellis. G–H. Basidiomata. Bars: A–D = 10 μm; E–F = 25 μm; G–H = 10 mm.
Reference:
Magnago, A. C., & Alves-Silva, G., & Henkel, T. W., & da Silveira, R. M. B. (2022). New genera, species, and combinations of Boletaceae from Brazil and Guyana. Mycologia 114, 607-625.
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