118 ALGAE IN PHYTOPLANKTON OF THE UNITED STATES 



Division Cyanophyta 

 Class Cyanophyceae 

 Order Hormongonales 

 Family Nostocaceae 

 GENUS CYLINDROSPERMUM Kiitzing, 1843 (fig. 53) 



MORPHOLOGY 



Cells are cylindrical and united into short, straight trichomes. Cells 

 range from 2 to 5 /*m in diameter. Trichomes are free floating or found 

 on moist soil. Heterocysts are cylindrical and always terminal. 

 Akinetes are contiguous to heterocysts. 



REPRODUCTION 



Reproduction is by heterocysts and akinetes. 



OCCURRENCE 



The genus commonly occurs in the tychoplankton and periphyton. 

 The more common species occur in hard-water, alkaline conditions. 



ENVIRONMENTAL CONDITIONS 



Standard 

 Range Mean deviation 



Temperature degrees Celsius 1.5 - 



pH 5.9 - 



Dissolved oxygen milligrams per liter 1.7 - 



Specific conductance micromho 35 



Total alkalinity milligrams per liter 3 



Total hardness do 6 



Total nitrogen do .10- 



Total phosphorus do .0 - 



SPECIES INFORMATION 



Refer to Geitler (1932) and Prescott (1962). 



