FUNGI: MUSHROOMS. 209 



426. Tube-bearing fungi (Polyporaceae). In the tube-bearing fungi, the 

 fruiting surface, instead of lying over the surface of gills, lines the surface 

 of tubes or pores on the under side of the cap. The fruit-bearing portion 

 therefore is "honey-combed." The sulphur polyporus (Polyporus sulphu- 

 reus) illustrates one form. The tube-bearing fungi are sometimes called 

 "bracket" fungi, or "shelf" fungi, because the pileus is attached to the 



Fig. 245. 



Edible Boletus. Boletus edulis. Fruiting surface honey-combed on under 

 side of cap. 



tree or stump like a shelf or bracket. One very common form in the woods 

 is the plant so much sought by "artists," and often called Polyporus ap- 

 planatus. It is hard and woody, reddish brown, brown or grayish on the 

 upper side, according to age, and is marked by prominent and large concentric 

 ridges. (This form is probably P. leucophaeus.) The under side is white 

 and honey-combed by numerous very minute pores. This plant is peren- 

 nial, that is, it lives from year to year. Each year a new layer is added to 

 the under side, and several new rings usually to the margin. If a plant 

 two or three years old is cut in two, there will be seen several distinct tube 

 layers or strata, each one representing a year's growth. 



In some of these bracket fungi, each ring on the upper surface marks a 



