CARTER: ILLINOIS TREES: THEIR DISEASES 



75 



Fig. 71. — Fungus strands produced under the bark of oaks affected with 

 shoestring root rot are slender, flattened, dark red, and rootlike in appear- 

 ance. The shoestrings, or rhizomorphs, that grow in the duff and soil 

 around diseased oak trees are black and round, and they measure about 

 one-sixteenth inch in diameter. 



Fig. 72. — The white, fanlike growth of the shoestring fungus produced 

 under the bark of diseased oaks is called a mycelial fan. 



