May 22 ,i 9 i6 Hypoderma Deformans 283 



It has been noticed repeatedly in nature that there is great irregularity 

 in the time between the first browning of the needles at their tips or at 

 other points along the needles and the appearance of the mature apothecia. 

 In a few cases the cycle of development from the first appearance of the 

 brown color at the tips of the needles to mature apothecia has been 

 observed to take place within the same calendar year, or from April and 

 May to November. More often infected needles first showed mature 

 spores in the spring of the following year. It was observed in a few cases 

 that the needles may lie on the ground through the following winter before 

 the apothecia rupture. Brown needles collected in August from infected 

 trees and placed in damp moss in the field in a number of cases developed 

 apothecia before January, maturing in May and June. The apothecia, as 

 previously indicated, may contain asci in various stages of development, 

 so that mature spores are being produced throughout the year. Investi- 

 gation has shown, however, the greatest number of spores are expelled 

 during the spring rainy season, May and early June, coinciding with the 

 greatest vegetative period of the host. In no instance, either in the field 

 or in artificial inoculation, were the infected needles of young trees or seed- 

 lings not previously attacked by the fungus killed before they had attained 

 their normal size. In September or October, such needles will have 

 assumed a more or less uniform reddish brown color. Mostly remaining 

 upon the tree, they may first produce the signs of the apothecia during 

 the late fall and mature the spores in the following spring. At the 

 time the foregoing experiments were in progress small bundles of infected 

 needles bearing fertile apothecia were bound with similar quantities of 

 needles which had died from a normal cause. These were placed in moss 

 during May, 1914. On examination in May of the following year the 

 needles which had died from a normal cause showed no signs of the fungus; 

 nor have they done so since that date. This apparently demonstrates 

 the inability of the fungus to act as a saprophyte. 



The foregoing observations and experiments apparently prove the 

 parasitism of the fungus. This is further substantiated by the observed 

 evidences that young seedlings in the field succumb to the ravages of the 

 fungus. Furthermore, it is indicated that the period of greatest infection 

 is during the growing season and only the needles of the season are to any 

 extent susceptible to attack. 



The fungus has not yet appeared in the forest nursery, but it may be 

 regarded as a possible nursery disease. 



PATHOLOGICAL EFFECTS OF THE FUNGUS ON THE BRANCHES 



OF THE HOST 



A very peculiar and at the same time interesting phenomenon 

 caused by the growth of the mycelium of the fungus in the shoot is the 

 formation of spherical-shaped witches'-brooms on trees mostly past 

 the seedling stage. These (PI. XXXII, fig. 2) brooms in old trees often 

 assume large proportions. A single witches' broom may weigh as high 



