Hapalosiphon hrasiliensis Borge 1918, p. 94 

 This species, like H. aureus, is here considered to be a small form 

 of H. pumilus. One of the characteristics which might be used to 

 separate it from the latter species is the difference in size between 

 the branches and the main filament. The cells are 7-9/a in diameter, 

 up to 27|U, long; filaments up to 11/a in diameter. 



Plants which agree with the description of H. hrasiliensis Borge 

 are found in the same habitat with the larger H. pumilus. 

 In Sphagnum bogs and soft water habitats. Wis. 



Hapalosiphon confervaceus Borzi 1892, p. 43 

 PI. 128, Fig. 4 



Filaments prostrate and creeping over submerged aquatics, 

 branching freely from both sides of the principal trichome; cells 

 quadrate or cylindrical, 8-12/* in diameter, 1-3 times the diameter 

 in length; heterocyst short- or long-cylindric, about the same size 

 as the vegetative cells; sheath thin, colorless, non-lamellated; fila- 

 ment 15-20/i, wide. 



Our plants are assigned here because of the habit of branching 

 and the shape and size of the cells, characters which agree with 

 the description of H. confervaceus Borzi. This species is described 

 as having calcareous deposits on the sheath, but the presence or 

 absence of such depositions is not a specific characteristic. Wis. 



Hapalosiphon fiexuosus Borzi 1892, p. 43 



PL 128, Figs. 5, 6 



Filaments tortuous, creeping and entwining about strands of 



submerged grass or bits of other aquatic plants, giving rise to long, 



curved branches from both sides; cells ellipsoid in the main trichome, 



becoming somewhat cylindric in the apices of the branches, 5.8-6.2/i, 



in diameter; heterocysts ellipsoid, 6.2/x in diameter, 7-8.5/x long; 



sheath thin, hyaline and without lamellations; filament 7.4-8ju, wide. 



In shallow water of a small grassy lake. Mich., Wis. 



Hapalosiphon hibernicus West & West 1896, p. 163 



A prostrate filament, either solitary or forming small entangled 

 tufts on submerged aquatics, branches unilateral and long, narrower 

 than the main filament and slightly tapering; cells quadrate-spherical 

 to long-cylindric, especially in the apices of the branches, 8.5-9.2/i, 

 in diameter in the main trichome; heterocysts short- or long-cylindric, 



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