REPORT OF THE 8TATE BOTANIST 



297 



Boletus scaber Fr.- 

 Rough-stemmed Boletus. 



Plate 35. 



Pileus glabrous or nearly so, commonly convex, the flesh white 

 or whitish ; tubes small, long, soon convex in the mass, depressed 

 around the stem, at first whitish, becoming darker, dingy or 

 brownish ; stem firm, solid, often narrowed at the top, whitish or 

 grayish, roughened with numerous small prominent, reddish or 

 blackish dots or scales ; spores oblong-fusiform, brown, .00055 to 

 .0007 in. long. 



The Rough-stemmed or Scabrous-stemmed boletus may well be 

 called our most common and, in respect to color, our most variable 

 species. Its cap varies in color from white to almost black. It 

 also varies somewhat in shape. It is generally convex or cushion- 

 shaped, but sometimes it is hemispherical or even broadly conical. 

 Its surface is commonly smooth, but occasionally specimens are 

 found in which it is slightly downy or even scaly. The flesh is 

 white or whitish, and the margin in mature plants is often thick 

 and blunt by reason of the lengthening of the tubes. 



The tubes are long and mostly convex in the mass in the 

 mature plants. They are much shortened around the stem, thus 

 leaving a depression or cavity there. When young and fresh they 

 are whitish, but they become darker and dingy or brownish with 

 age. Bruises or wounds of the whitish tubes and flesh sometimes 

 produce a slight change in color, it assuming pinkish or blackish 

 hues. 



The stem scarcely differs in any respect from the stem of the 

 Orange-cap boletus, and its characters need not be repeated here. 



Several varieties have been described, most of which depend 

 on the color of the cap. 



Yar. niveus has the cap white. Fig. 3. This is thought by 

 some to be a distinct species. 



Yar. aurantiacus has the cap orange-red. Fig. 4. This differs 

 from the Orange cap boletus only in the character of the margin 

 of the cap. 



Y&r.fuligineus has the cap fuliginous or cinereous-fuliginous. 

 Fig. 5. 



Ydir.fuscus has the cap brown or dark-brown. Figs. 2, 6 and 7. 



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