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 Add this item to the list  Trametes xanthopus (Fr.) comb. nov,
   
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Page number:177 
Description type:Non-original description 
Description:Trametes xanthopus (Fr.) comb. nov,
Polyporus xanthopus Fr., Syst. Mycol. 1 (1821) 350; Corner, Ann. Bot. 46 (1932) 71; Bose, S.R., Trans. Br. mycol. Soc. 20 (1936) 185, Microporus xanthopus (Fr.) O.K. (1898); Cunningham (1965) 152; Ryvarden and Johansen (1980) 440; Dutta S. and Anjali Roy, Nova Hedwigia 42 (1986) 1-7, ?Polystistus xanthopus Fr. var. florideus Bres., Hedwigia 53 (1912) 46; P, makuensis Cooke and P. luteus var. bukobensis P. Henn. f. Bres.
Pileus -19 cm wide, mesopodal from the first, infundibuliform or variously excentric, never truly pleuropodal, smooth or concentrically rugulose, glabrous, shining, very thin, fulvous ochraceous with narrow darker fulvous chestnut zones, paler towards the margin, often becoming wholly deep chestnut or bay brown, finally very dark to blackish when old; margin even, entire, or lobed in large specimens, white. Stem 3-50 x 1,2-4 mm, usually 8-20 x 2-2,5 mm, cylindric or slightly expanding upwards, dilating into the pileus with sharply delimited apex, glabrous, yellowish cream to pale ochraceous, often spotted ferruginous, arising from a concolorous discoid base 1,5-20 mm wide, velutinate at the periphery in a zone -6 mm wide of stiff hairs, the zone cracking on drying. Tubes 120-140 µm long, 80-100 µm wide, very short, white, abruptly delimited from the stem; pores 60-80 µm, wide, dissepiments 15-30 µm, thick with peltate edges, pure white. Flesh 300-600 µm, thick at the base of the pileus, dry, tough especially in the stem, white, with a very thin agglutinated crust.
On dead trunks, branches and sticks in lowland and montane forest. Pantropical (? neotropics), common in Malesia.
Spores 6-7,5 x 2-2,5 µm, white, smooth, subcylindric to suballantoid, thinwalled, aguttate, inamyloid; dried spores 5-6 x 2 µm. Basidia 9-13 x 3-4 µm, distally, 4-5 µm, at the base, subventricose; sterigmata 4, 2,5-3 µm, long. Cystidia and hyphal pegs none. Hyphae trimitic, clamped, not encrusted, the tissue distinctly dextrinoid with the dissepiments pale brown; skeletals 2-5 µm, wide, the walls thickening to obliterate the lumen, aseptate, unbranched, unlimited; mediate hyphae 12,5(-3) µm, wide, walls 1 µm, thick, some with few to several branches turning into skeletal or binding hyphae; binding hyphae 1-3 µm, wide, thick-walled with the lumen becoming obliterated, often much branched and coralloid, not flagelliform; generative hyphae 1,5-2,5(-3) µm, wide, clamped, thin-walled or some becoming rather thick-walled in the older tissue; dissepiments dimitic with narrow skeletal and generative hyphae, the ends of the dissepiments peltate from the divergent and often lobulate ends of the skeletals. Surface of pileus inoderm in an agglutinated layer 2030 µm thick and composed mostly of skeletal hyphae with pale yellowish to brownish walls and brownish to olivaceous droplets in their narrow lumina. Surface of stem with a similar crust 20-70 µm thick composed of binding and skeletal hyphae but becoming more or less structureless through agglutination. Disc at the base of the stem velvety with excrescent, unbranched, thick-walled, tapering, colourless hairs -450 x 4-5 µm -7 µm near their bases, as skeletal ends.
This description of living fruit-bodies is taken from that which I drew up nearly sixty years ago, and which I have repeatedly confirmed. For further details about the construction and growth of the fruit-body, I refer to that account (Corner 1932). Occasionally specimens are met with very pale pileus with or without more or less fuscous or greyish zones. Such may be good varieties.
Cunningham gives the spores as 3.5-4 x 2-2.5 µm Dutta and Roy give 3.6-4.2 x 1.3-1.9 µm I am unable to explain this short size unless it refers to immature spores. Ryvarden and Johansen give the same size as I have found, and my measurements were taken from many fresh spore-prints. Dutta and Roy also give the fruit-body as varying into the pleuropodal form and add the presence of short, slightly thickwalled, cystidioles. I have never observed either of these features; extremely excentric pilei may give the impression of being pleuropodal. Bose described specimens, from high altitudes in India, with unusually large, even irpicoid, pores, but his photographs are not convincing of specific identity. The dichophysial hyphae which Ryvarden and Johansen emphasize as peculiar to Microporus seem to me to be another way of describing the lobulate ends of the skeletals where they are displayed to make the peltate ends of the dissepiments. Recent descriptions of the species omit the two distinctive features of the peltate dissepiments, which render the pores narrower than the tubes, and the velvety disc at the base of the stem.
The species is listed as cosmopolitan. Yet, during two years in South America where I collected every different kind of polypore that I met, I never encountered Tr. xanthopus. I think that the American records may refer to the superficially similar fruit-bodies of Tr. xanthopodoides (p. 49), Flabellophora deceptiva and F. obovata var. A (Corner 1987).
The elegance of the refined fruit-bodies of Polyporus xanthopus, in contrast with the majority of Trametes, has prompted the distinction of Microporus but, on analysis, no sharp limits can be assigned to it, and I absorb the genus into Trametes (p. 10).
 
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