CONFERVA UMBROSA. 



C. filamentis ramofis repemibus fragilibus brevibus-obtufis, ramis cur- 

 vatis limplicibus fubfecundis articulis longis cylindraceis inflatifquc. 



C. umbrofa, Roth. Cat. Bot. I. p. 191. t. 4. f. 3. Fl. Germ. III. part. 1. p. 521. 

 C. Arenaria. Roth. Cat. Bot. II. p. 217.? 

 On Boggy Ground near Swanfea. 



THERE is every reafon to believe that the prefent fpecies is lufliciently com- 

 mon in certain fituations, though I am not aware of its having been noticed in 

 Britain, till I lately detected it on part of a bog, the furface of which had been 

 recently burnt, adjoining Singleton Wood, near Swanfea : probably however it 

 has been often patted by as a variety of C. frigida, to which, till placed under a 

 microfcope, it bears a great refemblance, but may be diftinguifhed by its growing 

 in fmaller patches, and by its darker color. It was firft difcovered by Dr. Roth, 

 who figured and defcribed it in the firft Fafciculus of his Catale&a Botanica, 

 under the name of C. umbrofa, and who, in the fecond Fafciculus, has given 

 another fpecies, under the name of C. arenaria, which I apprehend is only a 

 variety of the fame, as I have feen the joints fhort and inflated in one branch, 

 whilft in another on the fame plant they were cylindrical, and in length fully 

 equal to fix times their diameter. 



The filaments are creeping, and fo remarkably fragile, that it is difficult to 

 afcertain their length, which I believe never exceeds and feldom attains to half 

 an inch. There are generally four or five branches which are' limple, and mod 

 frequently difpofed on the fame fide of the ftein, but fometimes alternately ; 

 the apices are every where blunt : the diffepiments are more or lefs contracted 

 and divide the filaments into joints, which vary greatly in fhape and length, 



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