14 REMARKS ON THE DISTINCTIVE CHARACTERS 



of Great Britain, Professor Lindley and Mr Hutton have shewn that 

 attention to the structure as presented by longitudinal sections, is not less 

 necessary. The extension of my own observations, and the progress of in- 

 vestigation, have enabled me to come to more satisfactory conclusions, which 

 I now proceed to expose. 



The vegetable kingdom has been variously arranged. It is not, how- 

 ever, my intention to speak of the differences of opinion among botanists, 

 with respect to the grouping of plants. M. Adolphe Brongniart pro- 

 poses a distribution of vegetables into six great classes, as follows : 



I. AGAMIC PLANTS. 



These plants have an organization consisting entirely of cellular tissue, 

 or intersecting tubular filaments, are entirely destitute of leaves, and have 

 only, as organs of reproduction, very minute seminula, which appear to be 

 developed without fecundation, and which are contained immediately in 

 membranous conceptacles, similar to the filaments or cellules of the general 

 tissue of the plants. 



To this class belong the Algce, Fungi, and Lichens. 



II. CELLULAR CRYPTOGAMIC PLANTS. 



The plants of this class have an entirely cellular organization, but they 

 possess leaves having a structure and functions similar to those of the more 

 perfect vegetables. There are sexual organs, and the seminula are con- 

 tained in conceptacles of a very complex organization. 



This class contains the Hepaticce and Musci. 



III. VASCULAR CRYPTOGAMIC PLANTS. 



The cellular tissue, which is diversiform, almost always contains distinct 

 vessels, most commonly tracheae or false tracheae ; the leaves are highly de- 

 veloped, and furnished with cortical pores ; the stems are often very large 



