2(30 VEGETABLE ORGANOGRAPHY. 



In order to indicate these forms in a manner analogous 

 to the admitted terms, and at the same time to show 

 that there exists a difference, I think that it will be right 

 to reserve for the leaves of Palms the terms Pinnati- 

 FORM and Palmatiform, and for their pretended lobes 

 the name of Strips, which exactly expresses their 

 nature ; thus the leaves of Palms alone, in the vege- 

 table kingdom, answer to the idea which was formed, 

 before examination, of the divisions of leaves : these are 

 really entire leaves which are divided, whilst all the 

 others are portions, unequally joined together. This 

 tearing takes place after expansion, as in young Palms, 

 or before it, as is most frequently the case in old 



ones. 



All that we have hitherto explained relative to the 

 lobes of leaves, is applicable to the lateral ones of those 

 with pinnate or penniform nerves, and to the terminal 

 ones of those with palmate, palmiform, peltate or pedate 

 nerves ; but it now remains for us to speak of the emar- 

 ginations which are so frequently observed, either at the 

 base or apex of foliaceous surfaces. 



The emarginations of the base can by no means be 

 referred to the preceding theory, and result from simple 

 causes. In penninerved leaves it often happens that the 

 lower lateral nerves are larger and more developed than 

 the others; and their secondary ones are developed more 

 on the external side, where they find no obstacle, than on 

 the inner one, where they meet with those which spring 

 from the neighbouring nerve. It results from the deve- 

 lopment of these secondary nerves that the limb is pro- 

 longed beyond its origin ; or in other terms, that the base 

 of this limb has an emarginated appearance. When the 

 auricles thus produced are round, the limb is said to be 

 Cordate ; when they are pointed and directed parallel 

 with the centre nerve, it is Sagittate ; when they are 



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