4 Rhodora [JANUARY 
than its western relatives do theirs. The stimulus takes the form of an 
increased growth, both in length and in the number of branches. This 
growth is of two kinds. If a seed germinates on a weak branch, which 
is shaded or much crowded, the affected branch grows to be several 
times its normal length. After several years a very open system of 
branches has resulted. The lateral branches of the spruce are but one 
or two inches apart ; but on a large branch affected with the mistletoe, 
the points where lateral branches leave the main branch are often 
eight to twelve inche$ apart. Where a seed falls on a vigorous branch 
a very different form of branching results. Two stages of this are 
represented on the accompanying plate. The small branchlet nearest 
the germinating seed assumes a vertical position, and grows abnormally 
long during the first year. The next year several branches appear at 
its base, and both the main shoot and these fringing branches shortly 
give rise to others. After several years a very decided clump of 
branches grows in the form of a small bush, standing vertically on the 
horizontal branch. ‘The small bush or broom gradually appropriates 
the food supply of the branch, and that part of the main branch be- 
yond its base gradually weakens and dies. ‘Thus it may happen that 
ultimately the broom appears to be at the end of a strong branch. 
These brooms grow to be very large. On some of the tall spruces 
several were measured which were two feet wide and four feet high. 
A tall spruce covered with these brooms is truly a strange object. 
The leaves of the lengthened stems as well as those on the brooms 
are very much shorter than the normal spruce leaves, and paler in 
color, often quite yellow. ‘The age of the brooms varies with the vigor 
of the host tree. The brooms when once they cover a tree are a great 
strain on its vitality, and it very soon weakens and dies. Dead trees 
with the old brooms are surprisingly numerous on that portion of the 
Maine coast alluded to. That this seemingly obscure plant is very 
destructive to the spruce is evident. After the parasite has once ob- 
tained a foothold in a group of spruces, it will not be long before all 
are affected, thanks to the effective bombardment of their branches by 
the small fruit mortars. 
The manner in which the seeds are disseminated differs but little 
from that recently described by MacDougal.': A fact which Mrs. 
Millington speaks of in a letter to Dr. Engelmann is the way in which 
t MacDougal, D. T. Seed dissemination and distribution of Razoumofskya 
robusta (Engelm) Kuntze, Minn. Bot. Studies 2 Series, pt. II, p. 169, 1899. 
