PLITT AND PEssIN: ON DISTRIBUTION OF LICHENS 207 
Buellia parasema (Ach.) Th. Fr. 
The occurrence of this lichen began at one meter above 
ground, and from there on, it was distributed abundantly all 
over the tree. More than one hundred patches of this lichen were 
counted from the lower portion of the tree to the top. 
Candelaria concolor (Dicks.) Wainio. 
nly two patches of this species were found on the tree. 
Both were on the south side of the tree, and both just where a 
branch extended out from the trunk. 
Conotrema urceolata (Ach.) Tuck. 
This is perhaps the best represented species on the tree. 
In ascending the tree it was first found at one meter above 
ground on the north side of the tree. At first only small patches 
of it were present, but the higher one climbed the larger and 
more abundant became the patches of this lichen. From about 
seven meters above ground, the lichen became less and less 
abundant, so that at about eight meters from the ground there 
was no trace of it left. Apparently this lichen is an ombrophilous 
form, for it is found exclusively on the shady side of the tree in 
the northeast to northwest zones. 
Lecanora albella (Pers.) Ach. 
At about two meters from the ground only a small patch of 
this lichen was found. At about four meters from the ground it 
began to appear abundantly competing, as it were, with Cono- 
trema. Higher up the patches became more abundant. At 
about eight meters from the ground it reached its maximum 
distribution. Two meters above that this lichen did not appear. 
Lecanora subfusca (L.) Ach. 
Over thirty patches of this lichen were counted beginning 
above the lower third of the tree. This lichen occurred on all 
sides, and was especially abundant on the upper third of the tree. 
Lecanora varia (Ehrh.) Ach. 
Only two patches of this species were found. Both were on 
the upper third of the trunk. 
Lecidea vernalis.(L.) Ach. 
One small patch of this lichen was found on the south side 
of the tree at about two meters from the ground. 
