60 GROWTH OF MONOCOTYLEDONES. 



formed in the 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 monocotyledoneSy 

 having only one lobe to the seed,* whose growth re- 

 quires particular mention. To these belongs the natu- 

 ral order of Palms, which being the most lofty, and, in 

 some instances, the most long-lived of plants, have justly 

 acquired the name of trees. Yet, paradoxical as it may 

 seem, they are rather perennial herbaceous plants, hav- 

 ing nothing in common with the growth of trees in 

 general. Their nature has been learnedly explained by 

 M. Desfontaines, a celebrated French botanist, and by 

 M. ?ilirbel in his Traite d'Jnatomie et de Physiologie 

 F^getales, vol. 1. p. 209, and Linnaeus has long ago 

 made remarks to the same purpose. The Palms are 

 formed of successive circular crowns of leaves, which 

 spring directly from the root. These leaves and their 

 footstalks are furnished with bundles of large sap- vessels 

 and returning vessels, like the leaves of our trees. 

 When one circle of them has performed its office, an- 

 other is formed within it, which being confined below, 

 necessarily risies a little above the former. Thus suc- 

 cessive circles grow one above the other, by which the 

 vertical increase of the plant is almost without end. 

 Each circle of leaves is independent of its predecessor, 

 and has its own clusters of vessels, so that there can be 



^ Or i-alher no true cotyledon at all. 



