222 Rhodora [NOVEMBER 
The mistletoe was not equally in evidence on all trees showing 
equal transformation. On some it was produced sparingly, but on 
others it stood so high and thick on the branches as to hide the leaves 
and give a brown look even at some distance, the general effect being 
softened, however, by the green of the youngest twigs. The foliage of 
affected trees was usually of a paler and more yellowish green than 
the normal, but the comparatively few dead and dying trees showed 
that the mistletoe, although exhausting, was not so destructive a 
parasite as one would fancy. 
Isle au Haut is about the outermost island at the mouth of 
Penobscot bay, and fifteen to twenty-five miles from the mainland, ` 
although many small islands with spruce trees intervene. The locality 
here described is at Douglas (locally called Rich’s) cove, on the east 
side of the island looking toward the open ocean. The island, which 
is about six miles long and about half as wide, is well wooded through- 
out, chiefly with spruces and birches, and rises along the central line 
to over five hundred feet elevation, making the whole island into a 
miniature mountain range rising from the sea. The fogs roll in from 
the open ocean and envelop the eastern slope at all seasons, but ex- 
cepting in severe weather they are intercepted by the central summits 
and burned off before reaching the western shore, thus making a 
decided difference in the atmospheric humidity of the eastern and 
western slopes. To this difference in humidity, as suggested by Dr. 
von Schrenk, I am inclined to ascribe the fact that in my subsequent 
search, while I was able to find the mistletoe on the western slope of 
the island, it was never in sufficient luxuriance to cause witches' 
brooms or even noticeable fasciation of the branches. On the eastern 
slope only one area was found in which the majority of the trees were 
affected, but outside this area witches’ brooms of conspicuous size ` 
were not uncommon. 
I probably found more of the white spruce (Picea Canadensis 
B. S. P.— P. alba Link) affected than of the black spruce (P. Mariana 
B. S. P.— P. nigra Link), but I could see no indication of discrimina- 
tion by the parasite. I was more especially impressed with this 
observation, as the two spruces are similarly affected by climatic con- 
ditions, and have much darker foliage than when growing inland, in 
large part being of the same deep blue-green as the balsam fir (Adies 
balsamea Mill.), altogether making it difficult to distinguish them from 
each other except by a close scrutiny of the youngest twigs to detect 
