Viii PREFACE. 



Micrasteriasfoliacea, Bailey-Ualf& Desm. 210. Wordcn's ro.id, Rhode Island, Bailey. 



Miaraslerias Bayleyi, Ralfs. Desm. 211. Rliode Island, Bailey. 



Euadrum obloiigum, Ralfs. Des. 80. Rhode Island, Bailey. 



Euadrum crasmm, Kutz.-Ralfs. Des. 81. Rhode Island, Bailey. 



Euastrum ansatum, Eiirh.-Ralfs. Des. 85. E. hlnale Kntz. I'rovidence. 



Euastrum elegans, Kutz.-Ralfs. Des. 89. Providence. 



Euastrum binale, Ralfs. Desm. 91. Providence. 



Gosmarium cucumis. Corda.-Ralfs. Desm. 93. United States, Bailey 



Cosmarium Uocidatum, Ralfs. Des. 95. Providence. 



Gosmarium 3IenegJnnu, Breb. -Ralfs. Des. 90. United States, Bailey. 



Gosmarium crcnalum, Ralfs. Des. 96. Providence. 



Gosmarium amcenum, Breb. -Ralfs. Des. 102. Providence. 



Gosmarium or natum, RAhTS. Des. 104. Providence. 



Gosmarium connalum,BREii.-'RAhFS. Des. 108. Providence. 



Cosmarium Gucurhita, Ralfs. Dos. 109. Providence. 



Gosmarium grandituhcrculatum, Olney, n. s. ; "near G. cucumis, but with largo tubercles on the 



frond." Providence. 

 Staurast7-um orbiculare, Ralfs. Des. 125. Providence. 

 Slauraslrum hirsutum, Ualfs. Des. 127. Providence. 

 Slaurastrum Eyslrix, llALFS. Des. 128. Providence. 

 Slaurastrum gracile, Ralfs. Des. 136. Providence. 

 Slaurastrum telracerum, Ralfs. Des. 137. United States, Bailey. 

 HloMraslrum cyrtoceruyn, Rrf.b.-Ralfb. Des. 139. Providence. 

 Tetmemoras Brebissoni, Ralfs. Des. 145. Providence. 

 Tetmemoras granulalus, Ralfs. Des. 14G. Providence. 

 Penium margarilaceum, ljnETi.-l\iS.LFS. Des. {Glosterium Eur.) Providence. 

 Penium Digitus, Breb.-Ralfs. Des. 151. (Closlei-ium lamellosum.) 

 Docidium nodulosum, Breb.-Ralfs. Des. 155. Maine to Virginia, Bailey. 

 Docidium Baculum, Breb.-Ralfs. Des. 158. United States. Bailey. 

 Docidium nodosum, Bailey-Ralfs. Des. 218. United States, Bailey. 

 Docidium constridum, Bailey-Ralfs Des. 218 Worden's Pond, Bailey. 

 Docidium verrucosum, Bailey-Ralfs. Des. 218. Rhode Island, Bailey. 

 Docidium verticillatum, Bailey-Ralfs. Des. 218. Worden's Pond, Bailey. 

 Glosterium Lvnula, EnRH.-RALFs. Des. 163. New England, Baijey. 

 Glosterium moniliferum, Ehrii. -Ralfs. Des. 163. New England, Bailey. 

 Glosteriiem striolatum, Eiirh. -Ralfs. Des. 173. New England, Bailey. 

 CZos^enwm CM.sjrtda/in)!, Bailey-Ralfs. Des. 219. Worden's Pond, Bailey. 

 Pediastrum tetras, Ralfs. Des. 182. New England, Bailey. 

 Pediaslruvi heplactis, Ralfs. Des. 183. Providence. 



Pediastrum Boryanum, Menegh.-Ralfs. Des. 187. Maine to Mexico, Bailey. 

 Pediastrum ellipticiim, ETass. -Ralfs. Des. 188. Maine to Virginia, Bailey 

 Scencdcsmus quadricauda, Breb.-Ralfs. Des. 190. Maine to Virginia, Bailey. 

 Scenedesvms obtusus, Meyen. -Ralfs. Des. 193. Maine to Virginia, Bailey. 



