194 STUDIES OF AMERICAN FUNGI. 



minute. They scarcely can be seen with the unaided eye. Bruises 

 of the tubes turn brown, and certain " artists '' often collect these 

 plants and sketch with a pointed instrument on the tube surface. 

 For other peculiarities of this plant see page 15. The age of the 

 plant can usually be told by counting the number of the broader 

 zones on the upper surface, or by making a section through the 

 plant and counting the number of tube strata on the lower surface 

 of the cap at its base. 



Polyporus leucophseus Mont., is said to differ from this species in 

 being more strongly zonate, and in the crust being whitish instead 

 of reddish brown. 



Polyporus fomentarius (L.) Fr. \_Fomcs foment arms (L.) Fr.,] is 

 hoof-shaped, smoky in color, or gray, and of various shades of dull 

 brown. It is strongly zoned and sulcate, marking off each year's 

 growth. The margin is thick and blunt, and the tube surface con- 

 cave, the tubes having quite large mouths so that they can be readily 

 seen, the color when mature being reddish brown. Sections of the 

 plant show that the tubes are very long, the different years' growth 

 not being marked off so distinctly as in P. applanatus and leucophceus. 

 The plant grows on birch, beech, maple, etc. The inner portion 

 was once used as tinder. 



Polyporus pinicola (Swartz.) Fr.[Fomcspimcola (Swartz.) Fr.] occurs 

 on dead pine, spruce, balsam, hemlock spruce, and other conifers. The 

 cap is about the width of the F. applanatus, but it is stouter, and does 

 not have the same hard crust. The young growth at the margin, 

 which is very thick, is whitish yellow, while the old zones are red- 

 dish. The tubes are yellowish, and sections show that they are in 

 strata corresponding to the years' growth. Polyporus igniarius (L.) 

 Fr. [Fames igniarius (L.) Fr.J is a black species, more or less trian- 

 gular, or sometimes hoof-shaped. The yearly zones are smaller, 

 become much cracked, and the tubes are dark brown. One of these 

 plants which I found on a birch tree in the Adirondacks was over 80 

 years old. 



The genus Merulius has a fruiting surface of irregular folds or 

 wrinkles, forming shallow, irregular pits instead of a deeply honey- 

 combed surface. Merulius lacrymans (Jacq.) Fr., the" weeping" meru- 

 lius, or "house fungus," often occurs in damp cellars, buildings, 

 conduit pipes, etc. It is very destructive to buildings in certain parts 

 of Europe (see Figs. 189, 190). Merulius tremellosus Schrad., is very 

 common in woods during autumn. It is of a gelatinous consistency, 

 and spread on the under surface of limbs or forms irregular shelves 

 from the side (see Figs. 191, 192). 



