

112 Cushman : New England species of Closterium 



gewater! Lake Wat 



Length 310-560 /i; breadth 25-56 (i; apices 12.5— 18.6 «. 

 (Plate 3, figure 16 ; plate 5, figure 6.) 



Maine : Orono ( IV. West) ; Kittery ! Mud Pond, Township 

 6, Range 12 ! 



New Hampshire: Intervale ! Mt. Moosilauke ! 

 Massachusetts : Reading ! East Bri< 

 Fall River ! Milford Pond, Swansea ! 

 Rhode Island : Nyatt ! 



This species is recorded among the rare desmids of the United 

 States by L. N. Johnson, but it has been found frequently in New 

 England, as the above records show. It has usually been common 

 in the collections in which it has occurred. The delicate striae are 

 very noticeable on specimens from certain localities. Those from 



Lake WatUDOa and Nvatt haH tlipm in tVi*> mairtiihr nf ra^S. 



4a. Closterium didymotocum Johnsonii (W. & G. S. West) 



comb. nov. 



Closterium Johnsonii W. & G. S. West, Jour. Linn. Soc. 33 : 284. 

 //. 16. f. 1, 2. 1898. 



Cells more slender, about 17 times as long as wide, central 

 portion nearly straight with subparallel sides, ends gradually 

 attenuated and slightly curved; apices broad, truncated; ends 

 with the darker annular thickening, yellow-brown, smooth. 



Length 357//; breadth 21/*; apices 12 fi. 



New Hampshire : Plymouth ! (Type, H. J., no. 655) 

 The type of C. Johnsonii now in the collection at Harvard 

 University has been examined carefully. I am not satisfied that 

 the apparent sigmoid character of one semi-cell is more than acci- 

 dental. . The other semi -cell does not show it. The ends have 

 the annular thickenings and the broad truncate apices oi 



didymotocum. It is more attenuated than the typical and slightly 

 smaller. 



5. Closterium macilentum Breb. 

 Closterium macilentum Breb. Mem. Soc. Sci. Nat. Cherbourg 4 : 

 53- pl.2.f. 3 6. 1856. — Wolle, Desm. U. S. 38. pl.6.f- 6 - 



1884. — W. & G. S. West, Brit. Desm. 1 : 1 18. pi. 12. / 8-io- 

 1 904. 



Cells of medium size, 25-35 times as long as wide, nearly 

 straight, slightly curved toward the ends, apices obtusely rounded ; 

 cell-wall smooth, colorless. 



C. 



