VAUCHERIA. 55 



Mad. Near Bristol : fF. JV. Yoimg. About Edinburgh : Dr. 



GremJle. /(^^ 



This species would appear to be one of the rarest of the yj 

 genus. I have myself never encountered it. -^ 



8. Vaucheria sessilis Vaiich. 

 Plate lY. Fi^. 2. 



Char. Capsules pyriform, large, sessile. 



Ectosperma sessilis Yauch. Hist, des Conf. d'Eau douce, 

 Grev. Algie Brit. p. 192. ; Hook. Br. Fl. p. 320. ; Eng. 

 Bot. t. 1765. ; Harv. Manual, p. 148. 



This is one of the most abundant species of the genus. 

 The vesicles are almost as often solitary as in pairs ; and in 

 this state I apprehend it constitutes the Vaucheria dichotoma "" 



of writers. The spores are frequently noticed to be of a 

 reddish colour. This a2:)pearance is common to all the species 

 of the genus, and is probably the result of age, and also an 

 indication of the presence of azote. 



c. Vehicles pedunculate, in jjairs, lateral. 



9. Yaucheria geminata Vauch. 



Plate III. Fig. 1. 



Char. Capsules situated on a divided peduncle, common to 

 both. Anther intermediate. 



Ectosperma geminata Yauch. Hist, des Conf. p. 29. pi. ii. 

 fig. 5. ; Grev. Alg^ Brit. p. 193. t. 19 . ; Hook. Br. Fl. ,y 

 p. 320. ; Eng. Bot. t. 1766. ; Harv. Manual, p. 148. A^^ 



The filaments of this species are much finer than those of ^'^ 

 any of the preceding ; the seed-vessels, too, are smaller, and 

 represent a sphere hollowed out on the inner side, or towards 

 the anther. The peduncle is common to both seed-vessels : 

 after ascending for some distance from the filament from 

 which it rises, it sends off laterally two branches, on each of 



E 4 



