Phylum:Basidiomycota >> Class: Basidiomycetes >>  Order: Boletales 
 BCRC Number NO BCRC Number!  
 Scientific Name: Boletus balloui

Boletus balloui Peck, Bull. N. Y. State Mus. 157 : 22. 1912.

Basionym: Gyrodon ballouii (Peck) Smell, Mycologia 33: 422. 1941.

Tylopilus ballouii (Peck) Singer, Am. Midl. Nat. 37: 105. 1947.

 Description: Pileus 5.5 – 12 cm broad, convex to become depressed in the center, surface subglabrous, smooth or slightly pitted in the center, slightly viscid when wet, color orange to fulvous brown. Context whitish, turning dirty lilac when fresh, 1 – 2 cm thick at the central pileus. Epicutis a trichodermium of elongated cylindrical hyphae, 4 – 8 μm diam., golden succineous, inside granular and becoming orange brown to reddish brown in the Melzer's, rounded–obtuse at their free tips. Context hyphae of pileus 8 – 15 μm, orange–brown in Melzer's reagent. Tubes up to 1.5 cm long, somewhat depressed around the stipe. Pores 0.2 – 0.3 mm broad, subisodiametric or near margin somewhat radially elongated, concolorous with the tubes or cream to flesh color, stained brown when bruised. Stipe 8.5 – 16 × 0.9 – 4 cm thick, slender tapered toward apex, quite bulbous at base up to 1.8 – 4.0 cm thick, surface finely pruinose, glabrescent, dry, solid, often with the extreme apex striate just below the hymenophore, but not reticulated, veil none, basal mycelium whitish. Dermatocystidia 20 – 33 × 7 – 12 μm, clavate. Spore print yellowish or pale ochraceous cream. Spores 8.5 – 10.5 × 7 – 8 μm, ellipsoid to ovoid, frequently broadest below, often laterally bean-shaped, thin-walled, smooth without germpore, inamyloid. Basidia 30 – 36 × 10 – 13 μm, sterigmata four, 4 – 5 μm long. Pleurocystidia 40 – 75 × 9 – 12 μm, clavate to more or less ventricose, apexes obtuse, not appendaged and multiguttulate. Hymenophoral trama bilateral, with a melleous mediostratum of non-gelatinized 2 - 4.5 μm diam. hyphae; lateral stratum with strongly divergent, 2.7 – 8.3 μm diam. hyphae. Clamp connections absent.

Taiwan, Changhua: Erhshui, alt. 500m, 12 Aug 1998, Huang SI. s. n.

 Habitat: Scattered under broad-leaved trees.

Taiwan, China, Singapore, Malaysia, Japan, North America.


Chen, CM and Yeh, KW. 2000.


C. M. Chen

 Note: Distinguishing feature of this species was the relatively short spores and was one of the most intricate nomenclatorial problems (Singer,1947) as its short spores mostly belonging to genus Tylopillus and Gyrodon. But the tubes in Boletus are yellow at first and brown olivaceous as they mature, in contrast to the white or grey to pink or red in Tylopilus. In addition, this species has a convexo-plate pileus, not infundibuliform as in Gyrodon. This species is somewhat similar to B. peralbidus, even in color. Fortunately they can easily be distinguished by simple measurements of the breadth of the spores.