47 



ALGM FILIFORMES. 



Fai^iily SIPHONEiE. 



Characters. Algae composed of a continuous branched and 

 cylindrical cell Eeproductlve organs external. 



Genus VAUCHERIA D. C. 



Char. Frond here and there occasionally injlated. Repro- 

 ductive organs of two kinds, consisting of capsules and 

 anthercB or horns, lateral or terminal. 

 Vaucheria D. C. in Yaucli. Couf. ; Lyngb. Q6. t. 19. 23. ; 

 E. B. 1766. 933.; Flor. Dan. t. 1724. 1727.; Grcv. 

 A1q:» Brit. t. 19. JScfos2)erma Yaucli. Conf. t. 2, 3. ; 

 UnVr in N. A. N. C. xiii. p. 789. 140.; Conf. Sp. 

 Dilhv, t. 15, 16. 47. 74. 



Op all the freshwater AlycB none are more interesting or 

 more curious than those which we are about to describe. It 

 was from a knowledge of the reproduction of this genus, which 

 was first clearly made known by Vaucher, in his excellent 

 work on the Alyce, the only monograph at the period in ex- 

 istence devoted exclusively to the consideration of the fresh- 

 water division of the tribe, that naturalists were led to entertain 

 the notion of sexes in this class of plants, a notion which 

 even now it is by no means easy in all cases to discard. 



The Vaucheria are first described in this work, because 

 amongst the freshwater Algce they seem to stand alone, exhi- 

 biting no distinct relation to any other genus of that division 

 of the Alyce, although to the genera Codinm and Bryopsis, 

 amongst the marine species, they manifest a close affinity. 



The organs of reproduction of the Vaucherioi are of two 

 kinds, being composed of capsular bodies, and of filaments. 



