Fruitbody boletoid. Pileus scaly, smooth or tomentose, dry or viscid. Stipe scaly or reticulate, rarely smooth. Spores striate to ridged, but smooth in Boletellus projectellus. Clamp-connexions present. So far one species has been recorded in Europe, where this genus is not native.
Boletellus projectellus (Murrill) Singer
Pileus up to 14 cm broad, convex, almost flat when older, margin free, projecting and hanging straight down, surface dry, smooth, subtomentose, not cracked, brownish orange when young, becoming brownish red with age, not blueing when bruised. Stipe thick, mostly tapering upwards, with a coarse reticulum from top to the bottom, base covered with white mycelium; stipe surface yellowish when young, later becoming brownish yellow to reddish, unchanging when bruised. Flesh pale greyish orange turning slightly darker and flushed vinaceous near the cuticle when cut, in the stipe whitish to yellowish, buff at the base, slightly darkening when exposed to air. Tubes pale yellow when young, later olivaceous. Pores yellow when young, finally pale olive, unchanging when bruised. Smell not distinctive. Taste slightly acidic. Spores smooth, 27.3–36.4 × 7.8–13.3 μm, yellow in KOH. Pleurocystidia 82.9–85.8 × 15.6–23.4 μm, ventricose to subclavate, smooth, readily collapsing.
Habitat. Solitary to scattered in pine forests, mycorrhizal with pines (Pinus sylvestris and Pinus mugo).
Distribution. In Europe found very recently in Lithuania (Curonian Spit), where it is presumed to be an alien, although the exact path of introduction is yet unknown. The general distribution includes Eastern North America (USA, Mexico, Canada) and SE Asia (Taiwan).
Note. Among all the other European boletes Boletellus projectellus is easily recognized by the very large spores. Sometimes reffered to as Boletus projectellus.
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