Cladophora fracta var. normalis Rabenhorst ex Heering 1921, p. 44. 



Filament 80-120/i in diameter, very slightly branched, the branch- 

 es about the same diameter as the main axis, becoming attenuated 

 to about 25fx. Cells cylindrical, with thick, lamellate walls. 



In our collections a number of forms or expressions appear which 

 agree with descriptions and designations given by Heering {I.e., pp. 

 44-46). 



Floating in lakes. Mich., Wis. 



Cladophora fracta var. lacustris ( Kuetz. ) 

 Brand ex Heering 1921, p. 46 



[C fracta fa. subsimplex Kuetzing 1845] 

 PI. 20, Fig. 7 



A coarse, rigid form with very little branching, the branches 

 arising irregularly, often at right angles to the main axis. Cells long 

 and cylindrical, 25-60/x in diameter. 



This variety greatly resembles a form of Rhizoclonium because 

 of the almost total lack of branching. 



Floating. Mich., Wis. 



Cladophora glomerata ( L. ) Kuetzing 1845, p. 212 

 PI. 20, Figs. 8, 9; PI. 21, Figs. 1, 2 



Attached, forming dark green, fluflFy or streaming arbuscular 

 thalli, usually in flowing water. Filaments successively and regularly 

 branched, the branches usually crowded in the upper limits. Cells 

 very slightly attenuated toward the apices of the branches, which 

 are bluntly pointed. Main axis 75-100^ in diameter, 6-7 times the 

 diameter in length; cells in the branches 35-50/x in diameter, 3-6 

 times the diameter in length. 



This species is variable, and many forms are recognized. Few of 

 them seem to be sharply defined, and some authors regard the names 

 assigned to them as synonymous with other species. 



Attached to rocks and cement walls, especially in waterfalls and 

 rapids. Mich., Wis. 



Cladophora glomerata fa. Kuetzingiana 



(Grunow) Heering 1921, p. 39 



PI. 21, Fig. 3 



A form which is much more elongate and more loosely branched 

 than the typical. Main axis up to 74/a in diameter; branches 39-42/x 

 in diameter; ultimate branches 19-21/x in diameter. 



On stones along lake shores. Wis. 



[138] 



