58 A CATALOG OF ILLINOIS ALGAE 



P. viRiDis (Nitz.) Ehr. Boyer, loc. cit., p. 446 (1927). 

 Navicula viridis Kuetz. 



Thomas & Chase 1887, p. 330, as Navicula viridis: Cook, Chicago 

 — Lake Michigan. Agersborg 1930, p. 106, as Navicula viridis: 

 Macon, Decatur^ — warm waste-water ditch (Dec.-Feb.). 



P. VIRIDIS var. ELLIPTICA Meist. Mills, Index Diat., p. 1310 (1934). 

 Transeau: Coles, Charleston — ponds and small streams (Mar., 

 Apr.); Loxa^ — ditch (Apr.); Wrightsville — in a spring (Apr.). 

 Lawrence, Pinkstaff — pond (Nov.). 



PLEUROSIGMA W. Smith, 1852; Cleve, 1894 



P. ANGULATUM (Quek.) W. Smith. Boyer, Proc. Acad. Nat. Sci. 

 Phila. 79 (Suppl. 2): 471 (1927). 



Kofoid 1903, p. 516: Mason, Topeka — Quiver Creek (Jan., Apr., 



Sept., Oct.). 



STAURONEIS Ehrenberg, 1843 



S. ACUTA W. Smith. Boyer, loc. cit., p. 425 (1927). 



Thomas & Chase 1887, p. 330: Cook, Chicago — Lake Michigan. 

 S. ANCEPS Ehr. Boyer, loc. cit., p. 422 (1927). 



Transeau: Coles, Embarrass — small stream (Mar.); Mattoon 



—swamp (Apr.). Thomas & Chase 1887, p. 330; Ahlstrom 1936, 



p. 292: Cook, Chicago, Evanston— Lake Michigan. Agersborg 



1930, pp. 108-110, 113: Macon, Decatur — warm waste-water 



ditch (Dec.-Feb.). 

 S. ANCEPS var. birostris (Ehr.) CI. Hustedt in Pascher, Suesswass.- 

 fl. Mitteleur. 10: 256 (1930). 



Transeau: Coles, Charleston^ — creek (Mar.). 

 S. ANCEPS var. linearis (Grun.) V. H. Boyer, Proc. Acad. Nat. Sci. 

 Phila. 79 (Suppl. 2): 422 (1927); Mills, Index Diat., pp. 1454, 1462 

 (1934). 



Stauroneis linearis Ehr. 



Thomas & Chase 1887, p. 330, as S. linearis: Cook, Chicago — 



Lake Michigan. 

 S. gracilis Ehr. Boyer, loc. cit. (1927). 



Thomas & Chase 1887, p. 330: Cook, Chicago — Lake Michigan. 

 S. phoenicentron (Nitz.) Ehr. Boyer, loc. cit., p. 421 (1927). 



Thomas & Chase 1887, p. 330: Cook, Chicago — Lake Michigan. 

 S. phoenicentron var. amphilepta (Ehr.) CI. Mills, Index Diat., p. 

 1466 (1934). 



Transeau: Coles, Charleston — creek (Mar.); Loxa — ditch (Apr.). 

 S. PHYLLODES Ehr. Mills, loc. cit., p. 1467 (1934). 



Thomas & Chase 1887, p. 330: Cook, Chicago— Lake Michigan. 

 S. PRODUCTA Grun. Mills, loc. cit. (1934). 



Thomas & Chase 1887, p. 330: Cook, Chicago — Lake Michigan. 



