4$S £k¥PTOGAMIA. 



its seeds being dispersed under the cuticle 

 throughout, the membranous or gelatinous 

 substance of the frond ; Fucus, 1. 1066 — 

 1069, &c, whose seeds are collected to- 

 gether in tubercles or swellings, of various 

 forms and sizes ; and Conferva, of which 

 the 24th and 25th volumes of Engl. Bot.> 

 more especially, show various specimens. 

 This last genus is commonly known by its 

 capillary, and, for the most pa*rt, jointed 

 frond. The seeds of some species are 

 lodged in external capsules or tubercles ; 

 of others in the joints of the frond ; and 

 hence the ingenious Dr. Roth has formed 

 a genus of the former,, called Ceramium. 

 His RivuJaria, Engl Bot. 1. 1797—1799, 

 is perhaps more satisfactorily separated 

 from Conferva, as we trust is Vauchericu 

 i. I765, 1766, a fresh-water genus named 

 after M. Vaucher of Geneva, who has pub- 

 lished an elaborate and faithful microsco- 

 pical work on Fresh-water Confervas. The 

 submersed Algce in general are merely 

 fixed by the roots, their nourishment be~ 

 ing imbibed by their surface. Many of 

 them float without being attached to any 



