Leccinum andinum Halling, Mycotaxon 34: 106. 1989.
Pileus (4)911.5 cm broad, at first convex, with age plane, subviscid to tacky, entire to subrugulose, becoming even; disc even, at first brownish yellow, then raw sienna; margin subrugulose to uneven, when young grayish yellow, then brass yellow; surface subtomentose, becoming glabrous; maculose color spots present, amber yellow to brownish yellow to cinnamon brown to honey yellow to light orange to yellowish brown; sterile appendiculate flaps absent (but occasionally with a sterile zone). Flesh 720 mm thick, orange white to white to yellowish white, staining slightly blue to blue green; odor mild; taste mild. Hymenophore tubulose, depressed. Tubes 320 mm long, light yellow, becoming olive yellow, blue when injured; pores 23 per mm, deep yellow to yellow, then grayish yellow, blue green when bruised. Stipe 312 cm long, 1020 mm wide, equal to subequal to subclavate, dry; upper half when young densely scabrous, pale yellow, with age scabrous, grayish yellow; lower half when young scabrous, pale yellow, with age scabrous to subglabrous, grayish yellow; scabers on upper half when young yellow, with age brownish orange to brownish yellow to light brown to yellow ochre, on lower half when young yellow, with age brownish yellow; base white, staining not present. Stipe interior solid; flesh above when young yellow, with age yellow, staining blue; flesh at base when young marbled brown and white, with age marbled brown and white.
Basidiospores olive brown to umber brown, 14.723.8 µm long, 6.38 µm wide, mean Q = 2.88, smooth, ellipsoid to subfusoid to fusoid, dextrinoid, with KOH ochraceous. Basidia 31.540 µm long, 1215 µm wide, clavate, hyaline, 4 -sterigmate. Hymenial cystidia 5073 µm long, 511 µm wide, moderately abundant (more common near pores), thin walled, colored homogeneous contents or hyaline (rare), lageniform to ampullaceous to subfusoid to ventricose rostrate. Tube trama boletoid, hyaline, in KOH yellowish, lateral strata elements 27 µm wide, subgelatinous. Pileipellis hyphae a trichodermium, in KOH yellow ochraceous (sometimes with ochraceous homogenous contents), inamyloid; elements 2.85.6 µm wide, cystidioid to inflated to obtuse to slightly tapered to subcapitate, smooth. Intercalary cells subisodiametric, 1230 µm long, 1021 µm wide. Pileus trama interwoven, hyaline, inamyloid, with elements 3.510 µm wide, smooth, thin walled. Stipitipellis hyphae vertically oriented, parallel, giving rise to versiform caulocystidia, 3078 µm long, 312 µm wide, filamentous, with short-branched apices or subcylindric. Clamp connections absent.
Mycorrhizal host: Quercus.
The yellow to yellow brown colors and blue to blue green bruising reaction are good field characters. The association with oak, the yellow hymenophore and yellow context indicate placement in section Luteoscabra, but consistent bluing reactions have not been reported previously. First described from montane Colombia near Medellín, it is known in Costa Rica from sites near San Gerardo and Villa Mills in the Cordillera Talamanca.
Cite this publication as: Halling, R. E., G. M. Mueller, and M. J. Dallwitz. 1998 onwards. Leccinum and Phylloporus in Costa Rica: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 13 Decmber 2006. http://www.nybg.org/bsci/res/hall/deltaindex.html. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993 onwards, 1998) should also be cited (see References).