GROWTH OF MONOCOTYLEDONES. 5? 



rishment, and the means of increase, from 

 the leaf above it. 



By the above view of the vegetable cecono- 

 my, it appears that the vascular system of 

 plants is strictly annual. This, of course, is 

 admitted in herbaceous plants, the existence 

 or whose stems, and often of the whole in- 

 dividual, is limited to one season ; but it is 

 no less true with regard to trees. The layer 

 of alburnum on the one hand is added to the 

 wood, and the liber, or inner layer of the 

 bark, is on the other annexed to the layers 

 formed in preceding seasons, and neither have 

 any share in the process of vegetation for the 

 year ensuing. Still, as they continue for a 

 long time to be living bodies, and help to 

 perfect, if not to form, secretions, they must 

 receive some portion of nourishment from 

 those more active parts which have taken up 

 their late functions. 



There is a tribe of plants called monocoty- 

 ledoncs, characterized by having only one 

 lobe to the seed, whose growth requires par- 

 ticular mention. To these belongs the natural 

 order of Palms, which being the most lofty, 

 and, in some instances, the most long-lived 



