MISTLETOE INJURY TO CONIFERS..« el 
able trees. Considering the severity of the infection, they could 
not be expected to attain near the size of their parents shown in 
Plate III, figure 1, and from which they received the mistletoe. 
Of the 245 infected seedlings, 49 were dead. An examination 
of the root system of each 
seedling showed it to be well 
developed. In the absence 
of any other deteriorating 
influence except an occa- 
sional needle infested by 
Chionaspis pinifolia Fitch, 
the death of these seedlings 
must be ascribed to the lux- 
uriant growth of mistletoe 
which they had supported 
(fig. 5). In most cases the 
tufts of mistletoe had fallen 
away. The bark of the 
large fusiform swellings 
was usually ruptured and 
both the wood and bast tis- 
sues were so heavily infil- 
trated with pitch that the 
passage of food materials 
between the crown and the 
roots was wholly impossible, 
resulting in death. In this 
respect there is a parallel 
between this type of mistle- "S74 soy of Dou tr with toe nt 
toe Injury to seedlings and mofskya douglasii. Note the sparse foliage of 
: the upper crowns and the young brooms in the 
oO 
that resulting from the tree on the right, showing how the parasite 
perennial mycelium of some travels upward. The branches between the 
eaulicolus Peridermiums. brooms have died from lack of nourishment. 
A further study of the large trees shown in Plate ITI, figure 1, is 
illuminating. Two of them, the right and the left in the figure, are 
dead. Scarcely a single normal branch is to be seen, but instead are 
numerous large gnarled and distorted brooms. These trees measured 
on an average 9.3 inches in diameter at 44 feet from the ground, and 
increment borings showed the age of each to be 190 years. This is 
far below the diameter of normal trees of the same age for the 
region. <A careful search for secondary causes of injury resulted 
negatively. The trees were absolutely sound. Lightning injury, 
which sometimes causes spiketop in yellow pine and other conifers 
and which sometimes is erroneously attributed to mistletoe, was not 
present. With the evidence in hand, it is safe to state that the trees 
