130 VEGETABLE ORGANOGRAPHY. 



It is, then, quite certain that the stem exists in all 

 Vascular Plants — sometimes being large, at others small 

 — most frequently elevated into the air, but sometimes 

 subterranean. 



The general tendency of vascular stems is to rise per- 

 pendicularly from the ground in which they grow ; and 

 this fundamental property, which we mil hereafter 

 analyse, is only wanting in a very small number of vas- 

 cular plants — viz. Parasites, that is to say, those which 

 live upon the sap prepared by other plants — as, for 

 example, the Mistletoe and Dodder (Cuscuta). In 

 several cases this truth is scarcely e^ddent — as, for ex- 

 ample, when the stem or its branches are so feeble that 

 they cannot maintain themselves erect, or when the 

 stem is attached to the soil throughout its whole 

 length by roots or cramps; in these cases the ex- 

 tremities alone show the tendency to assume the vertical 

 direction. 



The ramifications of the stem have received the 

 names of Branches (rami; rameaux). The un- 

 divided part of the stem bears, in contradistinction, the 

 name of Trunk (truncus ; tronc) ; and the collection of 

 branches, that of Cyme (cyma; chve). These branches, 

 which are only kinds of stems, have a tendency, like 

 the trunk, to assume the vertical direction, especially in 

 their yomig state. We shall see hereafter that v/e 

 ought to consider each branch as a perfect whole, 

 inserted into the trunk or branch which gfives origfin 

 to it. 



The stem always bears the leaves, when it is destined 

 to liave any. There are no true stems without leaves, 

 except those of plants where these organs do not exist, 

 such as Orohanche, Lathrea ; and yet, in these cases, the 

 leaves are represented by scales, as in Lathrea, and also 

 Cuscufa ; or by tubercles, as in Stapelia. 



