8o TUFTS COLLEGE STUDIES, VOL. II, No. 3 



PAGE 



Family 7. Herposteiraceae 310 



8. Coleochaetaceae .... 312 



9. Trentepohliaceae 315 



Order V. Siphonocladiales 321 



Family i. Cladophoraceae 321 



2. Gomontiaceae 370 



3. Valoniaceae 371 



4. Dasycladaceae 377 



5. Sphaeropleaceae 384 



Order VI. Siphonales 385 



Family i. Codiaceae - 386 



2. Bryopsiclaceae 402 



3. Derbesiaceae 406 



4. Phyllosiphonaceae 407 



5. Caulerpaceae .... 408 



6. Vaucheriaceae 421 



List of works to which reference is made . . . 433 



Description of plates . . ... 456 



Index 463 



INTRODUCTION. 



In the following pages it is intended to give an account of the 

 green algae of North America, with as much detail as will en- 

 able the student to recognize the species, and have some idea of 

 their development and affinities. North America in this sense 

 includes everything from the Arctic Ocean to th'e Isthmus of 

 Panama, including the West India Islands. In the green algae 

 are included not only the Chlorophyceae, in the narrower sense, 

 but also the small class of the Heterokontae. On the other 

 hand two families are omitted, the Desmidiaceae and the Char- 

 aceae; the former, though closely related to the other Conju- 

 gales, has generally been taken as a separate study, for special 

 students ; to include it with as much detail as the other algae 

 would practically double the size of this work ; moreover the 

 American desmids are not well enough known at present. The 

 Characeae, on the other hand, are widel}' separated from all 

 other algae, representing the last term in a long line of develop- 

 ment, diverging from the main line at some remote time, so 

 remote that it is hard to guess at what point it started. 



