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IOWA ACADEMY OF SCIENCE 
Classification of Algae. The Classification which has been 
followed in the main in the arrangement of the various groups of 
the Algae has been that given by West in his “British Freshwater 
Algae.” He has, however, commenced with the higher or, more 
complex types and proceeds to the simpler and probably the more 
primitive types. We have altered this order, but otherwise the 
classification is much as is given. 
In the list of Algae keys to different groups have been included 
and also to the species of each genus of algae as far as they have 
been found in the state. These keys were prepared for the con- 
venience of the writer in making determinations and are here in- 
cluded because they may prove of assistance to others. In many 
cases these keys are taken directly from West, in others adapted 
from West or from Engler and Prantl, and many are original. 
While considerable care has been used in their preparation, never- 
theless, a key is but a clumsy device after all for purposes of identi- 
fication and these are submitted simply for what they are worth; 
it is to be understood that no attempt is made to differentiate the 
species found in the state from other species. Under each species 
in addition to the name and in a few instances some synonym, there 
have been given a few notes as to general distribution of the species, 
its Iowa localities as far as known reported to the writer or others. 
Included in some of the keys are genera and groups that have 
not been recorded for Iowa, but that undoubtedly occur. 
# 
Consideration of Species of Algae Found and Reported. 
KEY TO THE CLASSES OF ALGAE. 
I. Containing a blue coloring matter known as phycocyanin. The stored 
product of assimilation probably glycogen for the most part. Mostly 
fresh water Blue green Algae Myxophyceae 
II. Containing a brown coloring matter, diatomin (much resembling the 
phycophaein of the brown algae). Each cell with a siliceous covering. 
Universal in both fresh and salt water • Bacillarieae 
III. Containing a large proportion of yellow pigment known as xanthophyll. 
The stored product of assimilation is a fatty substance. Fresh water. 
Yellow green Algae Heterokontae 
IV. Containing only the green coloring matter known as chlorophyll. Stored 
product of assimilation usually starch. Usually fresh water. Green 
Algae Chlorophyceae 
V. Containing a brown coloring matter called phycophaein. Mostly marine. 
Brown Algae Phaeophyceae 
VI. Containing a reddish coloring matter known as phycoerythrin. Mostly 
marine • Rhodophyceae 
