206 NEBRASKA STATE HORTICUT.TURAL SOCIETY. 



Germination of the spores may not occur until after the timber has been 

 placed in position, where the moisture present will lead to the develop- 

 ment of the fungus. 



(9) Merulius lachrymans. Dry Rot: House Rot. 



This fungus is very similar in habits to the preceding, but is purely 

 a domestic fungus. The spores germinate on the surface of the wood 

 in warm, moist situations, and in the presence of an alkali, which is 

 necessary to the opening of a little plug in the spore covering. The 

 hyphae attack the medullary rays and the new wood. The mycelium 

 will cross from one timber to another on the intervening brick-work, 

 if that happens to be moist. Dry air is fatal to the mycelium. 



The following are found on timbers such as posts, ties and poles, 

 which are placed in position without proper seasoning: 



Polystictus versicolor — railroad ties in Minnesota and Texas. 



Lenzites sepiaria — on longleaf pine ties in Texas. 



Lenzites abietina — on softwood fence-rails and posts in Minnesota. 



Of an entirely different order of plants is the mistletoe which 

 attacks the lodgepole pine of the Rocky Mountains. It is described by 

 Morrell as follows: 



"There is a species of mistletoe on the lodgepole pine easily detected 

 by the presence of an abnormal growth of tufts of branches, commonly 

 called 'witches brooms.' These tufts soon die and the tree begins to 

 become 'spike-topped' (i. e., die at the top). Decay is not rapid, but 

 the tree dies in a few years, and the soon passes beyond use." 



The scientific name of this mistletoe is not given by Morrell, Razoum- 

 ofshya americana (Nutt) Kuntze, is noted by Rydberg (Flora of Col- 

 orado) as being parasitic on Pinus murrayana, contorta and divaricata; 

 R. cyanocarpa on Pinus flexilis; R. divaricata on Pinus edulis and 

 monophylla; and R. cryptopoda on Pinus scopulorum and ponderosa. It 

 thus appears that the pines have much to fear from the mistletoes. 

 In connection with the lodgepole, again, it is said that the trees 

 on the poorer qualities of soil are the most afflicted with this parasite. 

 This is doubtless due to the less thrifty condition of such trees, and 

 their increased tendency to fork, which is quite noticeable. 



In spite of the large number of these enemies of trees, of which I 

 have mentioned only a few, there has been found, as yet, very little 

 that it is practicable for the forester to do in the way of prevention 

 or cure. He can spray the seedlings in the nursery that are liable 

 to damping-off, and he can rid the beds of much of the organic material 

 which keeps the mycelium of the fungus alive. He may also be able 

 to spray the young trees which are affected with pine blister, if these 

 are in the nursery. He can protect his forest from the depredations 

 of cattle which would scar the trees and make openings for the entrance 

 of wound parasites. In the forests of Europe it is even found profitable 



