31 



II. Ulva. Linn. 



U. latissima, Linn. ; every where. 

 U. linza, Linn. ; New York Bay, &c. 

 U. bullosa, Roth. ; Newburgh. 

 6 Sp. ? or new. 



III. PoRPHYRA. Ag. 



P. vulgaris, kg. ; New York Bay, &c. 

 P. laciniata, kg. ; New York Bay, &c. 



IV. Bangia. Lyngb. 



B. fusco-purpurea, Dillwin ; Providence. 



Order IV.— OSCILLATORIACEiE. 



Marine or fresh water. Green, blue, or purple. Continuous, 

 tubular, but rarely branching Algae. Free, or enclosed in gelatine. 

 Contains six genera, namely — 



I. Rivularia. Roth. 

 II. Scytonema. Harvey. f 



III. Calothrix. Agardh. 



IV. Lyngbya. Ag. 



V. Microcoleus. Harvey. 

 VI. Oscillatoria. Vaucher. 



Genus I. — Rivularia. Roth. 



R. calcarea, Sm. ; Niagara Falls. 



R. atra, Roth. ; North River. 



R. angulosa, Roth. ; North River. 



II. Schytonema. Harvey. 

 S. oscillatum, Harvey ; Niagara Falls. 



III. Calothrix. 



C. confervicola, Ag. ; New York Bay. 



C scopulorum, Webb and Mohr ; Newport. 

 1 Sp. ? or new ; Greenport. 



IV. Lyngbya. Ag. 



L'. ferruginea, Ag. ; New York Bay. 

 L crispa ; Hoboken. 

 h.fulva, Harvey ; Stonington. 

 1 Sp. 1 or new. 



V. Microcoleus. Desmarest. 

 M. repens, Harvey ; damp ground. 



VI. Oscillatoria, Vaucher. 



0. Friesii ; Massachusetts. (Fresh.) 

 O. tenuissima, Ag. ; West Point. 



