•193 CRYPTOGAMIA. 



its seeds being dispersed under the cuticle 

 tliroughout the membranous or gelatinous 

 substance of the frond ; Fiiciis, f. 1066 — 

 106.9, &c., whose seeds are collected to- 

 gether in tubercles or swellings, of various 

 forms and sizes ; and Conferva, of which 

 the 24th and 2.5th volumes of Biisxl. Bot., 

 more especially, show various specimens. 

 This last genus is commonly known by its 

 capillary, and, for the most part, jointed 

 frond. The seeds of some species are 

 lodged m 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 Rivularia, Engl. Bot. t. 1797—1799, 

 is perhaps more satisfactorily separated 

 from Conferva, as we trust is Vaucheria, 

 t.1765, 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 Alga 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 



