AUTOBASIDIOMYCETES 



453 



that few may be classed as true parasites, the majority growing 

 upon logs, stumps, etc., after death, or after being felled. Some, 

 however, are unquestionably in part parasitic to the extent that 

 they may be considered disease-producing in woody plants. 



This species occurs extensively in the United States, principally 

 on the sugar maple (Acer saccharum), but also on other species 

 of deciduous trees. It is likewise found generally distributed in 

 Europe. The effects of this fungus upon the wood of diseased 

 trees has not been carefully studied, but there is certainly a heart 

 decay, probably more or less in the manner of some of the diseases 

 subsequently described. 



The sporophores appear in bracket-like clusters, which may be 

 20-30 cm. wide and 50-80 cm. or more in longitudinal extent. 

 The general color is creamy white, and the texture at first fleshy, 

 becoming more fibrous. The pileus, often 3 cm. thick, presents an 

 almost plain upper surface, slightly scaly, all of the pilei being 

 united posteriorly. Teeth slender and often 12 mm. long. This 

 is one of the largest fungi in this genus, and it is striking in 

 appearance. 



A number of species of this genus, or species of closely related 

 genera, particularly the resupinate forms, are found upon dead and 

 decaying wood. More beautiful and structurally differentiated of 

 the Hydnaceae, such as Hydniim erinaceus, Hydnum coralloides, 

 etc., are also found upon dead logs and trees and sometimes even 

 upon decayed portions of living trees. 



VI. WHITE ROT OF DECIDUOUS TREES 



Polyporus squamosus (Huds.) Fr. 



Buller, A. H. R. The Biology of Polyporus squamosus Huds., a Timber- 

 destroying Fungus. Journ. of Economic Biology 1 : 101-138. pis. j-g. 

 1906. 



The great scaly Polyporus, sometimes known as the Saddle-back 

 fungus, is a tree-destroying parasite whose conspicuous bracket 

 sporophores are in many regions well known upon ornamental, 

 shade, and forest trees. The fungus occurs throughout a large por- 

 tion of Europe, but it has been found as yet only sparingly, it 

 would seem, in the northern portion of the United States. The 



