MEMOIRS 
OF THE 
TORREY BOTANICAL CLUB 
Vol. VI No. 3 
The a History of Sphaerella lacustris (Haematococcus pluvialis) 
By Tracy ELLIOT Hazen 
(Prates 86, 87) 
Sphaerella lacustris has often been employed in biological text- 
books (generally under the name Haematococcus or Protococcus 
pluvialis) as the lowest type of plant life. It is a type which is of 
particular value for elementary study because of its clear 
morphological characters and interesting development and also 
because this development may be regulated with comparative ease 
for class work. 
Unfortunately, however, the treatment of the life history in the 
text-books is meagre and more or less marred by errors, Further- 
more, although numerous memoirs and abstracts on this subject 
have been published, they are for the most part inaccessible to 
American students, or (especially in the case of abstracts) are so 
filled with misconceptions due to insufficient personal observation 
as to be of little- value. 
It was with the purpose of clearing up such errors, and of 
furnishing an account of the life history of this type that might be 
available for students, that the present study of Sphaerella was un- 
dertaken over two years ago. 
In this report the first person has been frequently used because 
it was believed that the value of the account would be increased 
by thus clearly separating personal observations from previously 
published opinions. 
I wish to express my gratitude to Professor L. R. Jones, of the 
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