52 
IOWA ACADEMY OF SCIENCE 
Family I. 
Chamaesiphonaceae. 
I. Chamaesiphon. 
1. C. incrustans. Grun. Small round celled epiphyte. Cells 4 u. 
This form has been collected but once, then growing on the surface 
of some alga, probably an Oedogonium. 
Eagle Grove. Hewitt’s Pond. 1904. R. E. Buchanan. 
Family II. 
Chroococcaceae. 
KEY TO THE SUBFAMILIES OF CHROOCOCCACEAE. 
I. Ephiphytes, with well defined dorsiventrality Chroocysteae 
II. Free floating or in a gelatinous stratum, no dorsiventrality. . Chroococceae 
Subfamily I. 
CHROOCYSTEAE. 
None of the species belonging to this subfamily have been re- 
ported from Iowa, but it is probable that some of them, particularly 
the Gloeochaete, may be found attached to submerged mosses or 
algae. 
Subfamily II. 
CHROOCOCCEAE. 
This group includes many of the very lowest forms of the algae, 
some of them bearing evidence of their relationship to the bacteria. 
There is a considerable number of genera that are native to the 
state. 
KEY TO THE GENERA OF THE CHROOCOCCEAE. 
A. Cell division in two directions only, forming plane 7. Merismopedia 
B. Cell division in all directions of space, cells enveloped in mucus. 
* Cells forming large colonies. 
+ Cells arranged at or toward the periphery of large colonies. Spherical. 
=Cells closely and regularly arranged 2. Coelosphaerium 
== Cells geminate and sparsely scattered, markedly pyriform in shape 
3. Gomphosphaeria 
++ Cells densely aggregated in globose, elongated, or clathrate colonies 
4. Microcystis 
+++Cells aggregated to form irregular gelatinous colonies. 
= Individual mucous coats clearly evident around each cell 
5. Gloeocapsa 
== Cells involved in a common mucous covering (6. Aphanocapsa ) 
===Cells arranged in a compact gelatinous stratum. . .7. Porphyridium 
**Cells more or less solitary, or forming very small colonies. .8. Chroococcus 
1. Merismopedia. 
