368 



Diseases of Economic Plants 



hemlock, juniper, p. 384, larch, linden, 

 locust, maple, oak, orange, pear, pine, 

 poplar, Pseuclotsuga, spruce, walnut, 

 willow, and conifers and deciduous 

 trees generally. 



Polystictus. Ash, catalpa, mountain ash, and decid- 



uous trees generally. 



Poria. Birch, catalpa, fir, hemlock, juniper, pine, 



spruce, and conifers and deciduous 

 trees generally. 



Schizophyllum. Chestnut, horse-chestnut, mulberry, 

 many other trees. 



Septobasidium. Apple, oak, palmetto, tupelo, etc. 



Steccherinum. White cedar (Chamcecyparis) . 



Stereum. Birch, larch, oak, poplar, willow, 



drupes and pomes. 



Thelephora. Oak and trees generally. 



Trametes, p. 358. Birch, fir, hemlock, larch, locust, pine, 

 spruce, willow. 



Tricholoma. Deciduous trees. 



Volvaria. Trees generally. 



and 



and 



Canker, gall, twig-blight. — These diseases occur upon 

 nearly all kinds of trees. Galls are swollen parts, of the 

 general character illustrated in Figs. 44-212. Cankers are 

 bark diseases of varied extent (Figs. 10, 14). Twig-blight 

 consists of death of a twig through disease (Figs. 30, 214). 

 When occurring on valuable trees, excision or spraying may 

 be warranted, but on forest trees, manifestly no such treat- 

 ment is possible, and the only recourse is to adopt general 

 sanitary measures, particularly the burning of infective 

 material. 



The principal causes of these diseases with the hosts are 

 given below. Those with page references are given more 

 complete discussion on the pages indicated.* 



* References to books where descriptions of these fungi may be found 

 are given in the bibliography under numbers 390-394. 



