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IOWA ACADEMY OF SCIENCE 
Subfamily III. 
Tetraedrieae. 
1. Tetraedron. 
177. Tetraedron longispinum (Perty) Hausg. 
Ames. Bed of Creek below filter beds. Buchanan. 
Family VII. 
Palmellaceae. 
KEY TO THE SUBFAMILIES. 
Cells irregularly grouped in a structureless mass of mucus. . . .1. Palmelleae 
Cells grouped in four or sometimes irregularly disposed at the periphery of a 
structureless mass of mucus. Each cell with two pseudocilia 
II. Tetrasporeae 
Cells grouped in twos or fours within a lamellose mucous investment 
III. Gloeocystideae 
Subfamily I. 
Palmelleae. 
1. Palmella. 
178. P. mucosa Kuetz. 
Boone. Ledges. In slow stream. Buchanan. 
Subfamily II. 
Tetrasporeae. 
1. Tetraspora. 
179. T. lubrica Ag. 
Iowa City. Hobby. 
Ames. Bessey. 
Boone. Ledges. Buchanan. 
Ames. College spring. Buchanan. 
180. T. gelatinosa (Vauch) Desv. 
Iowa City. Hobby. 
Subfamily III. 
Gloeocystideae. 
1. Gloeocystis. 
181. G. gigas (Kuetz) Lagorh. 
Ames. Buchanan. 
Distribution of the Algae in General. Although conditions 
in Iowa are not generally suitable for the development of a large 
number of species of algae, yet there have been to date one hundred 
eighty species described as found within the state. Some of these 
forms are very local in .their distribution, others are found every- 
where. 
