Leccinum talamancae Halling, Gómez, & Lannoy in Halling, Kew Bull. 54: 750. 1999.
Pileus 26(8) cm broad, at first convex, with age plano-convex, dry to moist to viscid (in wet weather), even, becoming areolate to pitted to rugose to rugulose to wrinkled; disc even or rugulose or wrinkled, at first brownish gray to vandyke brown, then cocoa brown to vandyke brown; margin even or rugulose or wrinkled, when young cocoa brown to dark brown, then cocoa brown to dark reddish brown; surface subtomentose to matted subtomentose, becoming matted subtomentose to matted tomentose; sterile appendiculate flaps absent; with KOH orange brown to yellow. Flesh up to 8 mm thick, white, staining slowly pink to reddish orange; odor mild; taste mild. Hymenophore tubulose, adnexed to depressed to deeply depressed. Tubes 815 mm long, yellowish white, becoming brownish orange to mustard yellow, avellaneous when injured; pores up to 1 mm wide, white, dark reddish brown when bruised. Stipe 414 cm long, (4)1020 mm wide, equal to subclavate to clavate, strict or curved, dry; upper half when young finely scabrous and finely subpruinose ridged, white, with age finely scabrous to subpruinose, white; lower half when young scabrous, white, with age subscabrous ridged, white; scabers on upper half when young gray, with age black, on lower half when young gray, with age black; base white, staining blue green to deep blue. Stipe interior solid; flesh above when young white, with age white, staining pink to pinkish brown or reddish orange; flesh at base when young white, with age white, staining blue or greenish blue to dark blue; with NH4 bright grass-green at stipe base. Basal mycelium white, changing to blue when picked.
Basidiospores 17.522.4 µm long, 4.96.3 µm wide, mean Q = 3.5, smooth, elongate ellipsoid to subfusoid, inamyloid. Basidia 2534 µm long, 812 µm wide, clavate, hyaline, 4 -sterigmate. Hymenial cystidia 3070 µm long, 1020 µm wide, moderately abundant, thin walled, sometimes with gray brown contents or hyaline, lageniform to clavate-ventricose to subfusoid to clavate. Tube trama boletoid, hyaline, lateral strata elements 48 µm wide, subgelatinous. Pileipellis hyphae hymeniform (several cells in depth), inamyloid; elements up to 75 µm wide, cellular or subisodiametric and in sphaerocyst-like chains or subelongate, smooth or encrusted with pigment, thin walled. Intercalary cells isodiametric to subisodiametric or subcylindric (rarely). Pileus trama interwoven, hyaline, inamyloid, with elements up to 20 µm wide, smooth, thin walled. Stipitipellis hyphae vertically oriented, parallel, giving rise to clusters of caulocystidia, 30100 µm long, 920 µm wide, subfusoid to clavate to subclavate or lageniform (rarely), often with brown contents. Clamp connections absent.
Mycorrhizal host: Quercus.
The flesh is white at first when exposed, then becomes pink to reddish orange in the pileus and stipe apex. In mid-stipe the change is to a greenish blue and a deep, dark blue in the base of the stipe. These oxidation reactions appear to be consistent with this taxon. The pileus color seems to vary from a caramel to dark gray brown and typically is ±rugulose to rugose/wrinkled depending on individual collections. KOH is yellow to orange brown on the pileus surface. In a recent monograph of European Leccinums (Lannoy & Estades 1995), the Costa Rican material comes closest to L. variicolor Watling in subsect. Pseudoscabra. However, that species is apparently restricted to an association with Betula and the pileipellis elements are cylindrical in shape not isodiametric. At present, L. variicolor is unknown in the Americas, even though mycorrhizal host shifts have been documented and described for other agarics (e.g., Mueller & Strack 1992, Bougher & Malajczuk 1985, Bougher, et al. 1994). Clearly, more collecting in temperate and tropical America will provide a better picture of species composition and mycorrhizal associates.
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).