SOME PURE CULTURE METHODS IN THE ALG 
JACOB R. SCHRAMM 
Assistant to the Director of the Missouri Botanical Garden 
Instructor in the Henry Shaw School of Botany of Washington University 
INTRODUCTION 
Too much confidence has frequently been placed by algolo- 
gists in their ability to recognize a given species of alga among 
varying numbers of other species, and in the various forms 
which it may assume—a fact which has led to much confusion 
and error, especially among members of the Protococcales. While 
it is now definitely known that in a number of alge a single 
species may present markedly dissimilar appearances, either 
as a result of varying environmental conditions, or because of 
the presence in the life history of several unlike stages, it is cer- 
tain that much of the so-called polymorphism, or pleomorphism, 
of alge finds its explanation in inadequate methods of study. 
It is becoming recognized that for life history studies in the 
algee it is necessary to employ cultures free from other species 
of alge. Even in cases where this is not, on first thought, 
necessary, as in the large, filamentous forms, it should be ob- 
served, for the possibility of introducing spores or sporelings 
of closely allied species is by no means excluded in all cases. 
Gratifying progress has already been made by some algologists, 
working especially with members of the Volvocales and Pro- 
tococcales, and it seems reasonably certain that the originally 
chaotic condition existing in the latter will be ultimately reduced 
to complete order by a careful observance of the necessity of 
working with pure cultures, or at least cultures containing but 
a single species of alga. In life-history studies where physio- 
logical differences between species are to be investigated, it 
is especially desirable and indeed necessary to employ pure 
cultures. 
Certain species of alge, especially representatives of the 
Chlorophycee, have been much used in physiological investi- 
gations—chiefly those concerning themselves with various 
ANN. Mo. Вот. Garp., Vor. 1, 1914 (23) 
