494 
Some special phylogenetic Adaptations in Lichens.—, 
By ALBERT SCHNEIDER. 
In a previous paper* I endeavored to show why lichens should 
be considered as a distinct class of plants. It is my purpose in 
this paper to discuss briefly some of the special adaptive features 
which these plants have acquired since their phylogeny as lichens. 
I shall preface this discussion with a few introductory statements. 
Everywhere we can observe a balanced relationship between 
living organisms and their environment. All structures, no mat- 
ter where they may occur, or what form they may assume, serve 
a definite purpose and_ perform a definite function. In many in- 
stances the structural conformations are so “rudimentary” and 
“imperfect” that we are unable to recognize their physiological 
significance. It is however unscientific to say that such structures 
perform no function, because we are unable to recognize a func- 
tion. It were much more consistent to admit our ignorance and 
await further investigations, which may clear up some of the diffi- 
culties. J make these preliminary statements with special refer- 
ence to lichens, because many of their structural adaptations have 
as yet not been satisfactorily explained. I also wish to call at- 
tention to the importance and special biologic significance of the 
tendency among modern scientific botanists to point out the in- 
terrelation of structure‘and function. There is no function with- 
out structure: without structure there could be no function. 
From this it becomes evident that morphological and physio- 
logical investigations must go hand in hand. If we neglect one 
for the other we fall into a dangerous error, dangerous to the pro- 
gress of biological science. The time is fortunately slowly pass- 
ing away when morphology (usually external morphology) alone 
constitutes the science of life. The herbalists who go into wild 
ecstacies over having “ discovered” a “new species” are slowly 
giving way to the scientists who are solving or endeavoring to 
solve some difficult life-problem. The fact that many scientific 
efforts are fruitless in direct results is not a reason for becoming 
* The Biological Status of Lichens, BULLETIN, 22: 189-198. 1895. 
