Fink : Classification of Lichens 
101 
able plants in the vegetable kingdom, since it is the union of two 
separate plants, a fungus and an alga” (see also 44). This 
doubtful and confusing statement is left with little explanation, 
and the author of the book reaches the remarkable conclusion that 
since “the fungus forms the bulk of the lichen,” lichens should 
be regarded as fungi. The inconsistency of this statement needs 
only to be pointed out, and yet similar treatment is often found in 
text-books and elsewhere. The Bergen and Davis text (21) has 
it thus of lichens : “ They are not single plants, but composite 
organisms made up of algae which are contained in an enveloping 
mesh of fungal filaments.” This plainly makes the lichen a group 
of algae, though the authors had no intention of saying so remark- 
able a thing. The Bessey (22) text of 1906 is coherently correct, 
and the Bergen and Caldwell (20) text of 1911 is quite as coher- 
ently incorrect regarding the nature of lichens. These are fair 
samples of treatment of lichens in texts of general botany. 
Writers of texts on plant physiology have held nearer to the 
traditions concerning lichens and, consequently, have usually 
made more coherent statements, which have been almost uni- 
formly incorrect. 
On the whole, we can not regard the fundamentals of the lichen 
question settled so long as such confusing, incoherent and erro- 
neous utterances continue to emanate from leading botanists. 
Recent Expressions Regarding the Nature of Lichens 
We are still concerned primarily with the problem of the nature 
of the lichen and its relation to the algal host. The classification 
of lichens must be treated last of all, and can not be reached in 
this paper. Bessey (23,24,25,26) and Clements (35,37) have ex- 
pressed themselves to the effect that lichens are fungi and should 
be distributed to the exclusion of the group Lichenes. Reinke 
(105, 106) and Schneider (109, no, in, 112, 113), at the same 
time, have been stating at greater length that lichens are distinct 
from all other plants. When we have finally decided which side 
of the controversy is in accord with the facts established by re- 
search and are able to follow the conclusions reached in a logical 
manner, we may regard the problem of the nature and the proper 
treatment of lichens settled. 
