274 vegetablf. organography. 



Section VIL 



Of the Disposition of the Leaves upon the Stem. 



The disposition of the leaves upon the stem may be 

 considered either with regard to the parts of the stem 

 itself, or as to their succession in the duration of vege- 

 tation, or especially in reference to the comparison of 

 the leaves with one another. 



In the first point of view, which is the least impor- 

 tant, we distinguish them as Radical, Caulinary, 

 Ramal, and Floral. These terms, although easily 

 comprehended of themselves, require some explanation. 

 All leaves spring from the stem or the branches, and all 

 ought, consequently, to be classed under the terms 

 cauline and ramal : the two others also are only abbrevi- 

 ations to designate a complex idea ; those leaves are 

 called radical which arise so near the root that they 

 seem to proceed from it, and not from the stem ; such 

 are those of the Dandelion or the Hyacinth. There are 

 plants, such as those I have mentioned, and also Isoetes, 

 the stems of which are so short that during the whole 

 period of their existence they have only radical leaves. 

 There are others, principally biennials, the stem of 

 which remains very short the first year, so that during 

 this period all the leaves are radical ; the second year 

 the stem elongates, and is furnished with caulinary and 

 ramal leaves, the radical ones perishing : we see this in 

 most species of QLnothera and Verhascum. Lastly, 

 there are others, the stem of which is elongated and 

 provided with leaves, and bears also at the base other 

 leaves, in size and form so different from the ordinary 

 ones that they are obliged to be described separately, 

 under the name of radical leaves ; such are those of 



