118 Cushman: New England species of Closterium 



Worcester {Stone) ; Mt. Everett ( Wolle) ; Bridgewater ! Reading, 

 (zygospores) ! 



Rhode Island : Wainskut Pond, North Providence {Bailey). 

 The obliquely truncated and thickened dorsal margin of the 

 apices is very characteristic. 



* 14^. Closterium Dianae arcuatum (Breb.) Rabenh. 



Closterium arcuatum Breb. in Ralfs, Brit. Desm. 219. 1848. 

 Closterium Dianae arcuatum Rabenh. Flor. Europ. Alg. 3: 133. 



1868. — Wolle, Desm. U. S. //. 7. /. 8. 1884. — W. & G. 



S. West, Brit. Desm. 1 : 131. pi. T J. /. 2 r, 22. 1904. 



Slightly smaller and more strongly curved than in the typical 

 form, about 10 times as long as wide. 

 Length 190/i; breadth 19/i. 



Massac h 



* 



15. Closterium Pseudodianae Roy 



Closterium Pseudodianae Roy, Scottish Naturalist 10: 201. 1890. 



W. & G. S. West, Brit. Desm. 1: 132. //. 15. f. 7, 8. 



904 



Cells of medium size, moderately curved, 1 5-20 times as long 

 as wide, apices narrow and obtuse; cell-wall colorless or light 

 yellowish-brown, smooth. 



(P 



Length 15 5-2 54^; breadth 11.5-12.5/1; apices 2.5-3^ 





Massach 



Pond, North Falmouth ! 



Rhode Island : Nyatt ! 



Lake Watuppa, Fall River ! Cedar 



Dianae 



not nearly so common. It has not previously been reported from 



the United States. 



16. Closterium parvulum Nag. 



uostenum parvulum Nag. Gatt. einz. Alg. 106. //. 6 C. f. 2 (m 

 part). 1849. — Wolle, Desm. U. S. 45. pi. 7. /. 7. //. 8. /• 

 16. 1884. — W. & G. S. West, Brit. Desm. 1 : 133. pi I5> 

 f. 9-12. 1904. 



Closterium calosporum Cushman, Rhodora 7 : 115. 1905. 



Cells small, strongly curved, 10-12 times as long as wide, 

 apices acutely rounded ; cell-wall colorless, smooth. 





