Taxon Details: Tylopilus alkalixanthus Halling & Amtoft
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Macrofungi of Costa Rica Website Page: Tylopilus alkalixanthus Halling & Amtoft
Macrofungi of Costa Rica Website Page: Tylopilus alkalixanthus Halling & AmtoftFamily:
Boletaceae (Basidiomycota)
Boletaceae (Basidiomycota)
Scientific Name:
Tylopilus alkalixanthus Halling & Amtoft
Tylopilus alkalixanthus Halling & Amtoft
Primary Citation:
Tylopilus alkalixanthus, a new species of Boletaceae from Costa Rica and Japan.
Brittonia 54: 262-265. 2002
Tylopilus alkalixanthus, a new species of Boletaceae from Costa Rica and Japan.
Brittonia 54: 262-265. 2002
Accepted Name:
This name is currently accepted.
This name is currently accepted.
Description:
Latin Diagnosis: Basidiomata conspicua, pileus griseoflavus maturitate sordido luteus, maculis atrobrunneis, non vere viscosus, contextus albus, immutablis vel roseitintctus, sapor mitis vel leviter acerbus, tramae in kali causticum citrinus; stipes pileo concolorus; hymenium pseudocystidiis abundantis, hyphae laterales mediostratii concretionibus hyalinis helicis.
Macroscopic description: Pileus 50-100 mm broad, convex to plano-convex, grayish yellow, to light ochraceous buff to cream color to warm buff, with dark brown maculae, finely subtomentose, even at margins, dry, sticky when wet but not truly viscid. Context white, unchanging or changing to light pinkish, up to 15mm thick; odor mild, taste mild or slightly bitter. Hymenophore tubulose, adnexed to deeply depressed; tubes up to 20mm long, white to off white at first, becoming pinkish vinaceous to grayish red (7B-C4) with age; pores concolorous staining brownish. Stipe 60-170 mm long, 10-15 mm broad, elongate-subclavate, strict to curved, concolorous with pileus to slightly more yellow with age, staining slightly reddish brown with handling, even to slightly ridged, glabrous to finely subpruinose, whitish at base; context white to olive yellow, with olive yellow stains in base, unchanging when exposed.
Microscopic description: Basidiospores (7.7-9.1-11.9 x 4.2-4.9 µm, mean Q = 2.25 (n= 45, Lm = 10.46, Wm = 4.62), sub-fusiform to ellipsoid, smooth, hyaline to slightly pale melleous in KOH, inamyloid to weakly pseudoamyloid with only a few scattered spores reacting reddish-brown. Basidia (22.4-)25.2-30.1(-31.5) x 9.1-11.9(-12.6) µm, clavate, 4-sterigmate, hyaline in KOH, inamyloid. Hymenial cystidia 53.2-86.2 x 7-12.6 µm, highly abundant, predominately present as smooth, ventricose-rostrate pseudocystidia with a melleous amorphous to granular content, or very rarely not present as pseudocystidia but as smaller, hyaline cheilocystidia and pleurocystidia without amorphous content, pseudoamyloid. Hymenophoral trama divergent from mediostratum , releasing a lemon yellow pigment in KOH, lateral hyphae (4.9-)5.6- 8.4 (-9.8) µm wide, occasionally with hyaline helical wall thickenings, helical wall thickenings rarely present in mediostratum. Piliepellis a trichoderm of contorted hyphae 3-6.3(-7.0) µm wide, some with a pigment or content, solitary hyphae light yellowish brown, appearing darker brown in mass, pseudoamyloid. Stipitipellis a hymeniform of hyaline, clavate, obclavate, ventricose or filiform caulocystidia, 11.9-30.8 x 4.9-9.1 µm, with a few scattered hymenial pseudocystidia-like elements. Clamp connections absent.
Habit, habitat, and distribution: Solitary to gregarious on soil of montane forests dominated by Quercus oocarpa Liebm. in Costa Rica and Quercus Pinus foests in Japan. Infrequent and with a trans-Pacific distribution in the northern Cordillera Talamanca of Costa Rica and Costa Rica.
Paratypes: COSTA RICA. Cartago: Estrella, ±5 km E of Interamerican Highway at km 31, near town of Estrella, 9°46'4''N, 83°57'19''W; 1685 m, 6 June 1997, Halling 7700 (NY, USJ); 24 June 2000, Halling 7919 (NY, USJ).
Commentary: Twenty-three species of Tylopilus have been recorded from Mexico and Central America (Singer et al., 1991; Halling and Mueller, 2001; Halling, pers. obs.). Of these, none have the characteristics of T. alkalixanthus: a uniform, ochraceous pigmentation, mild taste, and a sometimes mutable context that releases a lemon yellow pigment in KOH. In addition, the helical wall thickenings on hyphae in the hymenophoral trama appear distinctive (Fig. 1C). Tylopilus alkalixanthus would appear to be allied to those taxa placed in section Oxydabiles as outlined by Singer (1986). There are still at least a half dozen additional taxa that remain to be described (Halling, pers. obs.) from Costa Rican Quercus forests, and some of the known ones need revision. Thus, a key to species is premature at this time.
Further commentary: After nearly a decade of collecting boletes in Costa Rica, I (R. Halling) have found the new species only at the type locality. Unfortunately, that site is threatened by encroaching land development. However, a specimen recently forwarded to us by Mr. Koichi Osaku from Japan agrees in all respects with the Costa Rican material. However, the quantity of lemon yellow pigment released in KOH is slightly less.
Discussion: This bolete has been found in Japan and its type locality near the town of Estrella in the northern Talamancas. Unfortunately, that locality is in danger of disappearing due to encroaching land development. Tylopilus alkalixanthus can be distinguished by its ochraceous basidiocarp with yellowish undertones, its mild taste, a context that is unchanging or changing to light pinkish, and the presence of scattered helical wall thickenings of the hymenophoral trama (below). The entire context of T. alkalixanthus gives a distinctive reaction in KOH by releasing a lemon-yellow pigment
Latin Diagnosis: Basidiomata conspicua, pileus griseoflavus maturitate sordido luteus, maculis atrobrunneis, non vere viscosus, contextus albus, immutablis vel roseitintctus, sapor mitis vel leviter acerbus, tramae in kali causticum citrinus; stipes pileo concolorus; hymenium pseudocystidiis abundantis, hyphae laterales mediostratii concretionibus hyalinis helicis.
Macroscopic description: Pileus 50-100 mm broad, convex to plano-convex, grayish yellow, to light ochraceous buff to cream color to warm buff, with dark brown maculae, finely subtomentose, even at margins, dry, sticky when wet but not truly viscid. Context white, unchanging or changing to light pinkish, up to 15mm thick; odor mild, taste mild or slightly bitter. Hymenophore tubulose, adnexed to deeply depressed; tubes up to 20mm long, white to off white at first, becoming pinkish vinaceous to grayish red (7B-C4) with age; pores concolorous staining brownish. Stipe 60-170 mm long, 10-15 mm broad, elongate-subclavate, strict to curved, concolorous with pileus to slightly more yellow with age, staining slightly reddish brown with handling, even to slightly ridged, glabrous to finely subpruinose, whitish at base; context white to olive yellow, with olive yellow stains in base, unchanging when exposed.
Microscopic description: Basidiospores (7.7-9.1-11.9 x 4.2-4.9 µm, mean Q = 2.25 (n= 45, Lm = 10.46, Wm = 4.62), sub-fusiform to ellipsoid, smooth, hyaline to slightly pale melleous in KOH, inamyloid to weakly pseudoamyloid with only a few scattered spores reacting reddish-brown. Basidia (22.4-)25.2-30.1(-31.5) x 9.1-11.9(-12.6) µm, clavate, 4-sterigmate, hyaline in KOH, inamyloid. Hymenial cystidia 53.2-86.2 x 7-12.6 µm, highly abundant, predominately present as smooth, ventricose-rostrate pseudocystidia with a melleous amorphous to granular content, or very rarely not present as pseudocystidia but as smaller, hyaline cheilocystidia and pleurocystidia without amorphous content, pseudoamyloid. Hymenophoral trama divergent from mediostratum , releasing a lemon yellow pigment in KOH, lateral hyphae (4.9-)5.6- 8.4 (-9.8) µm wide, occasionally with hyaline helical wall thickenings, helical wall thickenings rarely present in mediostratum. Piliepellis a trichoderm of contorted hyphae 3-6.3(-7.0) µm wide, some with a pigment or content, solitary hyphae light yellowish brown, appearing darker brown in mass, pseudoamyloid. Stipitipellis a hymeniform of hyaline, clavate, obclavate, ventricose or filiform caulocystidia, 11.9-30.8 x 4.9-9.1 µm, with a few scattered hymenial pseudocystidia-like elements. Clamp connections absent.
Habit, habitat, and distribution: Solitary to gregarious on soil of montane forests dominated by Quercus oocarpa Liebm. in Costa Rica and Quercus Pinus foests in Japan. Infrequent and with a trans-Pacific distribution in the northern Cordillera Talamanca of Costa Rica and Costa Rica.
Paratypes: COSTA RICA. Cartago: Estrella, ±5 km E of Interamerican Highway at km 31, near town of Estrella, 9°46'4''N, 83°57'19''W; 1685 m, 6 June 1997, Halling 7700 (NY, USJ); 24 June 2000, Halling 7919 (NY, USJ).
Commentary: Twenty-three species of Tylopilus have been recorded from Mexico and Central America (Singer et al., 1991; Halling and Mueller, 2001; Halling, pers. obs.). Of these, none have the characteristics of T. alkalixanthus: a uniform, ochraceous pigmentation, mild taste, and a sometimes mutable context that releases a lemon yellow pigment in KOH. In addition, the helical wall thickenings on hyphae in the hymenophoral trama appear distinctive (Fig. 1C). Tylopilus alkalixanthus would appear to be allied to those taxa placed in section Oxydabiles as outlined by Singer (1986). There are still at least a half dozen additional taxa that remain to be described (Halling, pers. obs.) from Costa Rican Quercus forests, and some of the known ones need revision. Thus, a key to species is premature at this time.
Further commentary: After nearly a decade of collecting boletes in Costa Rica, I (R. Halling) have found the new species only at the type locality. Unfortunately, that site is threatened by encroaching land development. However, a specimen recently forwarded to us by Mr. Koichi Osaku from Japan agrees in all respects with the Costa Rican material. However, the quantity of lemon yellow pigment released in KOH is slightly less.
Discussion: This bolete has been found in Japan and its type locality near the town of Estrella in the northern Talamancas. Unfortunately, that locality is in danger of disappearing due to encroaching land development. Tylopilus alkalixanthus can be distinguished by its ochraceous basidiocarp with yellowish undertones, its mild taste, a context that is unchanging or changing to light pinkish, and the presence of scattered helical wall thickenings of the hymenophoral trama (below). The entire context of T. alkalixanthus gives a distinctive reaction in KOH by releasing a lemon-yellow pigment