204 NEBRASKA STATE HORTICULTURAL SOCIETY. 



fungus attacks the roots, where the spores germinate, and the mycelium 

 enters the bark and passes up through the cambial layers into the 

 wood, and finally into the stem of the tree. A violet discoloration of 

 the wood first takes place, the cells drying up and later becoming brown- 

 ish yellow. The elements of the wood are finally separated like so many 

 fibers of asbestos. The mycelium may extend up into the trunk to a 

 height of twenty-five feet, and finally, when all of the roots have been 

 permeated, the death of the tree results. 



(6) Polyporus species — Red Rots. 



Concerning the longleaf pine (Bull. 13, Div. of Forestry), Dr. Mohr 

 writes as follows: 



"Frequently fullgrown trees are found to show signs of rapid decay. 

 These are recognized by the gradual dying of the smaller limbs, and 

 their falling off, in consequence of the rotting of the wood surrounding 

 their base; and after having been cast off a hole or diseased spot 

 remains in the trunk, which is infested by a large fungus of the genus 

 Polyporus (Punk holes, punk stools). The heartwood of such trees is 

 of a reddish color, soft, sappy, and full of small channels caused by the 

 breaking down of the walls of the wood cells, filled with the mycelium, 

 the so-called spawn of the fungus, the threads of which also penetrate 

 the medullary rays. Such punky or red-heart timber is found mostly 

 on the ridges on the poorest soils. Apparently superannuated trees are 

 most affected with this rot." 



Further, in Alabama, this is almost unknown on the shortleaf. In 

 northeastern Texas it affects only superannuated trees. The loblolly falls 

 prey most frequently on account of its more sappy wood, and the fungus 

 progresses in this very rapidly. 



Concerning the lodgepole pine, Mr. F. W. Morrell writes from the 



Holy Cross Forest Reserve, Colorado: 



"The most destructive disease of the lodgepole is a red-rot of the 

 Polyporus order, which is quite prevalent in our district. It attacks 

 mostly the mature trees, though it may be found occasionally in smaller 

 ones. Forked-topped trees are especially liable to attack, probably be- 

 cause of the excellent lodging and germinating facilities offered by the 

 crotches. A noticable habit of the disease is its irregularity throughout 

 the trunk. A log of sixteen feet in length will frequently be found sound 

 at both ends, but badly decayed in the middle, and vice versa. Logs 

 in which it occurs are of little use. They have a reddish appearance, 

 and are brittle and powdery. A similar fungus attacks Engelmanti 

 spruce." 



(7) Shoe-stritig Fungus: Tree Root Rot. Armillaria mellea: Agaricus 



melleus Cke. 



This very common agaric is one of the most destructive enemies of 

 the coniferous forests of Europe, and in this country is at least a series 

 enemy of the white pine. Concerning the occurrence and habits of this 

 species, in relation to white pine, Spalding writes: 



"It also fastens upon various deciduous trees as a parasite, attacking 

 living trees of all ages, but living as well upon dead roots and stumps 



