76 ALGAE IN PHYTOPLANKTON OF THE UNITED STATES 



Division Chrysophyta 

 Class Bacillariophyceae 

 Order Pennales 

 Family Eunotiaceae 

 GENUS EUNOTIA Ehrenberg, 1837 (fig. 32) 



MORPHOLOGY 



Cells are solitary or joined valve to valve into chains. They are free 

 floating or epiphytic. Cells are rectangular, linear, or tabular in girdle 

 view. Both girdles and valves are strongly ornamented, generally with 

 intercalary bands. Valves are arcuate having similar poles and 

 dissimilar margins. The concave side is regular; the convex side is in- 

 flated slightly near the poles and is regular or undulate. A short raphe 

 extends from evident polar nodules diagonally to the concave side. 

 There are no central nodule, costae, nor septae. Two chromatophores 

 are laminate. 



REPRODUCTION 



A single auxospore is formed by the conjugation of protoplasts from 

 2 approximate cells. 



OCCURRENCE 



The genus is found commonly in bodies of soft water and in slowly 

 moving waters. They are frequently found in oligotrophic or dystrophic 

 waters (Patrick and Reimer, 1966). 



ENVIRONMENTAL CONDITIONS 



Standard 

 Range Mean deviation 



Temperature degrees Celsius 0.0 



pH _ 3.4 



Dissolved oxygen milligrams per liter .8 



Specific conductance micromho 23 



Total alkalinity milligrams per liter 



Total hardness do 3 



Total nitrogen do .06 



Total phosphorus do .0 



SPECIES INFORMATION 



Refer to Boyer (1927a) and Patrick and Reimer (1966). 



