26 



II. Gjgartina, Lamour. 

 Cartilaginous, cylindrical filaments in gelatine. Fruit in external 

 tubercles. Tetraspores massed in dense sori sunk in the frond. 

 G. mamillosus, Goodwin and Woodward ; N. Y. Bay. 

 G. purpurascens, Lamour ; Stonington. 

 G. 2 Sp. ? or new. 



III. Gymnogondrus. Lamour. 



Filiform, dichotomous, horny, dense structure. Favellae in spongy 

 warts. 



G. plicata, Lamour ; N. Y. Bay and Sound. 



IV. Chondrijs. Lamour. 



Cartilaginous flabelliform, cleft, dense. Tetraspores in sori, im- 

 mersed. 



C. mammillosus, Greville ; L. I. Sound. 

 C. Crispus, Lamour ; L. I. Sound. 

 C. Brodaii, Greville ; Rhode Island. 



C. Norvigicus, Lamour, ; Mass. Bay. 



V. Phyllophora. Grev. 



Stalked, rigid, dense, bearing a nerveless leaf. Tubercles scat- 

 tered over the leaf. Warts seated on the frond, composed of 

 radiating filaments, which become spores, Tetraspores in sori on 

 the leafllets. 



P. BrodiecB, Greville ; N. Y. Bay. 



P. rubens, Lam. ; Mass. Bay. 



P. Sp. ? or new. Apalachicola. 



VI. POLYIDES. 



v Frond cylindrical, cartilaginous, solid. Fruit, spongy warts. 

 Tetraspores cruciate, immersed in the filaments of the frond. 

 P. rotundus, Grev. ; Rhode Island. 



VII. Ftjrcellaria. Lamour. 



Frond cylindrical, cartilaginous, solid, and forked. Tetraspores 

 deeply imbedded in swollen apices of the frond. 

 F . fastigiata, Hudson; Newburyport. 



VIII. Dumontia. Lamour. 

 Frond tubular, filled with thin gelatine. Spores in the inner sur- 

 face of the frond. Tetraspores among the surface cells. 



D. ramentacea, Lamour ; Stonington. 



IX. Halymenia. Ag. 



H.florensia; Florida. 

 H. ligv.lata; Florida. 

 H. furcellata, Agardh ; Newport. 



