Polyporales » Polyporaceae » Atroporus

Atroporus diabolicus

Atroporus diabolicus (Berk.) Ryvarden 1973, in Palacio et all., Plos one, 12(10), e0186183 (2017).

Diagnosis: Basidiomata annual to biannual, central to eccentrically stipitate, solitary; pileus circular, up to 3.2 cm in diameter and 4 mm thick; pilear surface reddish black (10R2.5/1) to very dark red (2.5YR2.5/2), glabrous, radially striate to finely wrinkled; margin rounded/truncate, sterile, with a black cuticle. Pore surface light brown (7.5YR6/4) to dark brown (7.5YR3/2), in some specimens a black cuticle covering the surface; pores circular, regular, 5-8 per mm, 90-140(± 150) μm (ave = 111.5 μm, n = 80/2); dissepiments entire, 30-100.5(±120) μm thick, (ave = 51.1 μm, n = 80/2). Tubes concolorous with pore surface, not stratified to stratified into 3 layers, up to 7 mm long each one. Context homogeneous, light brown (7.5YR6/4), 1.5 mm thick. Stipe cylindrical, solid, glabrous, longitudinally striate, bearing a black cuticle up to 3.2 cm long, up to 5 mm diam., with a robust appearance. Hyphal system dimitic with generative hyphae and skeletal-binding hyphae. Generative hyphae with clamps, hyaline, thin-walled, 2±3 μm thick, difficult to observe. Skeletal-binding hyphae of two types; arboriform type, present in stipe and context, up to 230 μm long, 2.5±4 μm wide, thick-walled, with a short unbranched stalk (17.5-48 μm), 4±6 branches with an alternating arrangement, and shortened as getting closer to the trama of the tubes, hyaline to yellowish in KOH and water, IKI- (Figures 3A and 4A). In the trama of the tubes are present the second type of hyphae (Figs 3C and 4B), skeletal-binding hyphae short (41-75 μm long) and "prickly" always with acute apex that is projected above hymenium, golden yellow in KOH and water, strongly dextrinoid changing to dark brown in Melzer reagent, thick-walled, just after the septa (3±5 μm wide) developing a stalk, that is considerably enlarged at the central portion (7-11 μm wide), between the middle portion and apical portion arise 2 to 6 branches (1-3 μm wide), stalk ending in an acute apex, as small spines, at angles 75o-90o, generally longer towards the base, which can reach up to 76 μm long, sometimes with dichotomous branches. Basidia clavate, 4-sterigmate, with a basal clamp, 1922 × 68 μm. Cystidia and chlamydospores absent. Basidiospores ellipsoid, thin-walled, hyaline, smooth, IKI-, CB-, (5.0-)6.0 (-7.0) × (2.0-)3.0-3.5 μm, (ave = 6 × 3 μm), Q = 1.7-2.5, (ave = 2, n = 40).

Index Fungorum Number: IF309367

Notes: Atroporus diabolicus is characterized by the presence of strongly dextrinoid skeletal- binding "prickly" hyphae with a pointed apex in the trama of the tubes that arises above the hymenium, the rounded/truncate and sterile margin and the robust appearance of the basidiomata. Atroporus dibolicus is microscopically similar to A. rufoatratus and A. infernalis, however A. rufoatratus has tramal skeletal-binding hyphae developing a stalk that tend to be slightly longer and narrower (4993 × 28 μm), with a rounded and projected apex (lacking spine-like short branches), similar to those of A. infernalis. Macroscopically, A. infernalis is hitherto known by a short and lateral stipe with pileus flat and flabelliform, A. diabolicus is central to eccentrically stipitate with pileus flat and circular, and P. rufoatratus centrally stipitate with pileus circular, depressed to slightly infundibuliform.