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 Add this item to the list  802407 Original description
   
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Page number:327 
Remarks (internal):Leccinellum quercophilum can be identified by its association with oaks, the dull brown or yellowish brown rugulose-pitted cap that becomes conspicuously areolate, the fine brown scabers, the green and blue staining, and the trichoderm pileipellis. It has been thought to represent the European species Leccinum griseum (Quél.) Singer (≡Gyroporus griseus Quél.) by various North American authors, including Smith & Thiers (1971: 214). However, the name Leccinum griseum is problematic (Lannoy & Estades 1995; den Bakker & Noordeloos 2005). Regardless of its correct name, this European species, sometimes listed as Leccinum carpini (R. Schulz) D.A. Reid (Lannoy & Estades 1995) or Leccinum pseudoscabrum (Kallenb.) Šutara (den Bakker & Noordeloos 2005), is primarily associated with Carpinus and does not stain blue or green (except very rarely in the base of the stem). Also, the European species has yellowish tubes when young and flesh that stains deep violet when sliced (Lannoy & Estades 1995; den Bakker & Noordeloos 2005)-a difference noted by Smith & Thiers (1971). On the basis of these morphological differences, we recognize the North American species as new and have selected an epithet reflecting its association with oaks.
Leccinellum Bresinsky & Manfr. Binder was erected in 2003 (Bresinsky & Besl 2003) to accommodate Leccinum species with a yellow hymenophore and a trichoderm-like pileipellis. Boletus nigrescens Richon & Roze (nom. illegit.; ≡ Leccinellum nigrescens (Singer) Bresinsky & Manfr. Binder) was designated as the type of the genus. Bresinsky & Besl (2003) included Leccinum carpini and L. griseum among eight existing species they accepted in Leccinellum, but the nomenclature and taxonomy warrant review. Although the hymenophore of Leccinellum quercophilum is not yellow, it falls within Leccinellum as defined in Bresinsky & Besl (2003) on the basis of its pileipellis.
GenBank BLAST searches with an ITS sequence of Leccinellum quercophilum reveal that the closest matches include Leccinum carpini [AF454588.1 (The Netherlands)], Leccinum crocipodium (Letell.) Watling [AF454589.1 (Belgium), JN021053.1 (France), JF908325.1 unpublished (Italy), and AF454590.1 (The Netherlands)], and Leccinum talamancae Halling et al. [AY544779.1 (Costa Rica)] as labeled and numbered in GenBank with published citations (den Bakker et al. 2004a,b; Dentinger et al. 2011). The >3% difference in sequence identity supports Leccinellum quercophilum as a distinct species. Morphological differences also separate these taxa. As noted above, the European species associated with Carpinus has yellowish young tubes, flesh that turns violet when sliced, and does not stain blue or green; Leccinum crocipodium has a yellow hymenophore and does not stain green (den Bakker & Noordeloos 2005); Leccinum talamancae is less areolate and features flesh that turns slowly pink to reddish orange in the pileus and stipe apex when exposed (Halling 1999). Our own additional unpublished alignments and phylogenetic analyses, along with the ITS tree in Lebel et al. (2012a,b), support generic placement in Leccinellum. Further research will determine whether Leccinellum as presently circumscribed is or is not supported phylogenetically.
 
Description type:Original description 
Description:Leccinellum quercophilum M. Kuo, sp. nov. Plate 2
MycoBank MB802407
Differs from Leccinum griseum by its bluish green staining on the pileus and stipe, its creamy whitish tubes, its context staining gray when sliced, and its association with Quercus in eastern North America.
Type: United States, Illinois, Coles County, Charleston, under Quercus alba on a lawn, 12 July 2008, coll. M Kuo 07120801 (Holotype, NY; GenBank ITS KC691207, LSU KC691208).
Pileus 3-9 cm broad; convex; dry; glabrous; dull orangish brown (OAC 749) to medium yellow-brown (OAC 707, 715); rugulose-pitted when young, becoming conspicuously areolate; without an overlapping sterile margin; discoloring bluish green marginally with age; surface negative with the application of ammonia or FeSO4, negative to yellowish with 15% KOH. Hymenophore tubulose; depressed at the stipe. Tubes 1-2 cm deep, creamy whitish (contrasting with the pore surface), discoloring slowly blackish when sliced; pores 1-3 per mm at maturity, round becoming angular with maturity, whitish or medium grayish brown (OAC 736) when young, becoming yellowish brown to brownish; discoloring greenish in places with age; bruising slowly dark brown, with or without a bluish stage. Stipe 5-9 cm x 8-20 mm; equal, or tapered slightly to apex, or slightly ventricose; dry; whitish underneath fine, tiny scabers that are whitish apically and brown below; the scabers arranged in vague longitudinal lines, darkening somewhat with age but not blackening; bruising or staining greenish to bluish basally; basal mycelium whitish. Context whitish, staining grayish to gray within 15-30 minutes of being sliced, with or without a faintly pinkish stage; sometimes staining bluish in the stem base when sliced; pinkish to negative with the application of ammonia, negative to greenish with FeSO4, gray to greenish gray with 15% KOH. Odor and taste not distinctive.
Basidiospores 15-18(-28) x 5-7.5 µm; fusiform; ochraceous in 2% KOH; inamyloid; aseptate; smooth. Basidia 25-30 x 9-12 µm; clavate; tetrasterigmate. Pleurocystidia 25-40 x 8-12 µm; occasional or frequent; fusoid-ventricose; thin-walled; smooth; hyaline to ochraceous or golden in 2% KOH. Cheilocystidia 35-50 x 5-10 µm; fusoid-ventricose to mucronate, subclavate, or irregular; thin-walled; smooth or roughened; ochraceous to golden in 2% KOH. Caulocystidia 30-50 x 10-15 µm; mostly fusoid-ventricose but occasionally ventricose-rostrate, or lageniform; apices occasionally mucronate; thin-walled; smooth; hyaline to ochraceous in 2% KOH. Pileipellis a trichodermium of septate hyphae; hyaline to ochraceous or brownish in 2% KOH; terminal elements subglobose to clavate or irregular, 25-50 µm wide.
Ecology & distribution - Scattered to gregarious under oaks; appearing in hardwood forests and in urban settings (lawns, cemeteries, etc.); summer and early fall; currently known from Illinois and Michigan.
 
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