New England desmids of the sub-family Saccodermae 



Joseph Augustine Cushman 



The sub-family Saccodermae contains many of the least con- 

 spicuous of the desmids and also as a rule those which are apt 

 to be overlooked, as is shown by the fact that previous to the 

 writer's work on the New England species there were but fourteen 

 species and varieties known from New England. In the present 

 paper twenty-seven species and varieties are noted, for all of which 

 New England specimens have been seen by the writer. While 

 this doubles the number previously known, it is small when com- 

 pared with the number known in the British Isles, fifty-seven 

 species and varieties being recorded by W. & G. S. West in their 

 recent monograph. In the genus Spirotaeuia for instance, there 

 are fourteen species recorded by the Wests from the British Isles, 

 while from New England there are three (one up to the time of the 



i 



present paper). This difference will probably be somewhat lessened 

 with further collecting, especially in the White Mountain region 

 where conditions are very favorable for certain forms. 



In the preparation of the present paper material was examined 

 from all of the New England states and such of the material of 

 previous writers as is available. Material from Vermont and 

 Connecticut has however been disappointing and not in any 

 quantity. All the localities from which actual specimens have 

 been seen by the writer are indicated by an exclamation point. 

 Recent work has shown errors in the previous work and so far 

 as known these are indicated in the brief synonymy given. The 

 generic position is much changed from that in Wolle's Desmids 

 of the United States, and his references are given whenever he 

 has recorded the particular species. The forms new to the New 

 England flora are marked by an asterisk. 



In most points the monograph of the Wests has been followed. 

 Free use has been made of their keys where they are given. At 

 the end of the present paper is given a simple key to the New 



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