124 Cushman : New England species of Closterium 



Cells very large, about four times as long as wide, slightly con- 

 cave close to the apices, dorsal margin broadly convex, ventral 

 margin slightly tumid. 



Length 800/* ; breadth 170//. (Plate 5, figure 7.) 



Massachusetts : Milford Pond, Swansea ! 



This is one of the largest of our desmids and is visible without 



a lens. 



27. Closterium littorale Gay 



W 



ium littorale Gay, Monogr. Conj. 75. pi. 2. f. 17. 1884. 

 & G. S. West, Brit. Desm. 1 : 155. pi. 19. f. 14. I9°4- 



Cells rather small, about nine times as long as wide, slightly 

 curved, inner margin tumid in the middle, gradually attenuated to 

 the obtusely rounded apices ; cell-wall colorless, smooth ; zygo- 

 spore globose and smooth. 



Length 160-164// ; breadth 18-18.5 ! x '< diameter of zygospore 



28//. (Plate 4, figure 8 ; plate 5, figure 12.) 

 Massachusetts : Eastham, with zygospores ! 

 This is the first record for the zygospore of this species. New 



to United States. 



28. Closterium tumidum Johnson 

 idum Johnson, Bull. Torrey Club 22 : 



291 



/. 4. 1895. — W. & G. S. West, Brit. Desm. 1 : 156. pl- J 9' 

 f. 15-18. 1904. 



Closterium Cornu, forma major West, Jour. Bot. 339. 1888. 



Cells rather small, 8-9 times as long as wide, slightly curved, 

 inner margin prominently tumid in the middle, gradually attenu- 

 ated to the truncately rounded apices ; cell-wall colorless, smooth. 



Length 130-150/i; breadth 14-18/i. 



Maine : Orono ( W. West). 



New Hampshire : Holderness, frequent (Johnson, W. & &■ 

 S. West) ; Pudding Pond, North Conway ! 



29. Closterium abruptum West 



Closterium abruptum West, Jour. Roy. Micr. Soc. 1892: 7 l 9- 

 pl. 9. f. 1. 1892.— Johnson, Bull. Torrey Club 22: 291- 

 P l - 2 39- f- 5- 1895. — W. & G. S. West, Trans. Linn. Soc. 

 Bot. II. 5 : 236. pl. ij. f. 14, i 5 . 1896 ; Brit. Desm. I : *5 8 - 

 pl. 20. f. 6-10. 1904. 

 Cells rather small, about 12 times as long as wide, slightly 



