88 ILLINOIS ACADEMY OF SCIENXE 



and prairie areas. It is quite variable in form under 

 these various circumstances. Fide Collins. 



Draparnaldia Ravenellii Wolle. 



Common in old prairie ponds, thus far not seen in the 

 ponds of the upland forested region. It is common, 

 however, in the bottom land ponds of the Wabash 

 river south of Lawrenceville and Vincennes. This 

 very distinct form has been known only from the col- 

 lection made by Ravenel in South Carolina. The long- 

 est specimen noted attained a length of 27 centimeters. 

 Fide Collins. 



Pleurococcus vulg'aris Meneghini. 



\'ery abundant on slightly shaded rocks, trees and 

 fences. Absent in forests. 



Herposteiraceae 



Herposterion confervicola Xaegeli. 



Common in ponds and pools on various filamentous 

 algae. 



Coleochaetaceae. 



Coleochaete irregularis Pringsheim. 



Rather common in temporary ponds. Fruits in late 

 spring and summer. 

 Coleochaete Nittelarum Jost. 



Found on Chara and Nitella in Hodgen's and the east 

 Big Four ponds. Fruits in mid-summer. 

 Coleochaete orbicularis Pringsheim. 



Collected from the pond at the west end of Polk street, 

 Charleston, April, 1912. 

 Coleochaete scutata Briebisson. 



Very common in ponds both permanent and temporary. 

 Have found it fruiting- sexually in late May and June. 



Siphonocladiales. 



Cladophoraceae. 



Rhizoclonium hieroglyphicum (Ag.) Kuetzing. 



\'ery abundant in streams and ponds- It is not unusual 

 to find the prairie streams fairly choked with a growth 

 of this alga in ]\Iay and June. In the ponds it is com- 

 monly associated with species of Cladophora. Fide 

 Collins. 

 Rhizoclonium fontanum Kuetzing. 



Rather common in ponds. Have never found it in a 

 branched condition. Occasionally it occurs on the 

 moist soil of pond margins. Fide Collins. 

 Cladophora glomerata (L.) Kuetzing. 



The common species of the streams of eastern Illinois. 



