A 



JOURNAL 



OP 



NATURAL PHILOSOPHY, CHEMISTRY, 



AND 



THE ARTS. 



MAY, 1812. 



ARTICLE I. 



On the Fructification of the Plants of the Class Cryptogamia. 

 In a Letter from Mrs. Agnes Ibbetson. 



Ik 



To Mr. NICHOLSON. 



sm, 



my last letter I showed the dissection of fresh-water Difference of 

 plants, endeavouring in a particular manner to mark thek°| gya " d 

 effect produced in different vegetables by the more or less 

 water which surrounded them in their growing state; and 

 proving, that those large divided air vessels are to be found 

 *n fresh-water plants alone ; the vessels decreasing as the 

 ditch, in which they were in the habit of growing, approach- 

 ed more to boggy or wet ground instead of water. This 

 is truly exemplified in what I have called the half-water 

 plants : there are however a few exceptions to this rule ; 

 and, since I last wrote, one has occurred to me in the arum, 

 which, though long removed to tolerably high ground, still 

 retains its immense air vessels. But in comparing fresh- Marine plants 

 water plants with marine plant?, the alteration and transition 

 is excessive. Instead of large bladders of air, circular wood 

 Vol. XXXII, No. 146.—May 1812. B vessels 



