26^ 



PHYTONOMY. 



simpler than the later, as, for example, that the root leaves 

 are simpler than the stem leaves, there are, however, many 

 apparent exceptions in the Acacias of New Holland, the first 

 leaves of which are separated into many parts, while those 

 that come later appear to be simple. These later leaves, 

 however, are rather intermediate forms between the leaf-stalk 

 and the leaves. These last have not arrived at their evolu- 

 tion ; they have thus become abortive, and the leaf-stalks 

 supply their place, (181.) 



389. 



Another law to which the consideration of the evolution of 

 plants leads us, is that of numerical proportion. As all divi- 

 sion and unfolding of parts proceeds from the spiral vessels, 

 and where these fail, from the sap-vessels, no other division, 

 according to the rule formerly given (279), can be fundamen- 

 tal, but that which proceeds from one to three ; because two 

 new vessels always place themselves on the sides of the origi- 

 nal spiral vessels. Hence, the number three prevails in all 

 the lower organic bodies, as far as the Amaranth eae. By 

 doubling this number we have six, and by tripling it we have 

 nine. Hence Butomus and Hydrocharis belong to the same fa- 

 mily. In more perfect plants two new vessels place then[|selves 

 on both sides of the original spiral vessels, and in them, there- 

 fore, the number five must prevail, the double of which gives 

 ten. When we perceive a fourfold and eightfold subdivision, 

 \ve may assume an abortion or union of parts, as the law of 

 nature in these cases, (L78.) 



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