62 MORPHOLOGY. 



each other, is that of the nodus with leaf, and leaf with 

 leaf, the normal position of which latter is their alterna- 

 ting with each other in a spiral direction along the axis ; 

 but becoming opposite or approximating by the conflu- 

 ence of the nodii. 



k. In the progression of the leaf three kinds may be 

 seen the ensheathed leaf or coleophyllum, the petio- 

 lated one or steleophyllum, and that destitute of petiole 

 but having the lamina or placophyllum. 



/. The common and true leaves are especially des- 

 tined through the means of the inspiration and expira- 

 tion of aerial fluids to increase and better the condition 

 of the juices ; but it becomes otherwise in respect to 

 those metamorphoses which always accompany the pro- 

 duction of the germ. 



m. At the summit of all metamorphoses of the leaf 

 exists a generative function, the pistillar leaf of the fe- 

 male part closing the morphological series ; but these 

 generative leaves do not follow immediately upon the 

 green ones, their types, but between them exists another 

 series. 



n. The change of the leaf up to the coloured and 

 sexual one, is the ascending metamorphosis ; in the 

 descending metamorphosis is shown the return of these 

 to the green leaves again. 



o. A metamorphosis of the leaf is seen where instead 

 of the evolution of a leaf-bud or twig from its axilla, 

 that of a blossom or flower takes place ; the change is 

 into a bractea, but which is the same in function, and 

 approaches very closely to its original type 



p. In the flower itself the axis almost vanishes as 

 regards development in length, and the metamorphosed 

 leaves instead of being placed individually above each 

 other with evident internodial spaces, become approxi- 

 mated and confluent, although in some cases there are 

 sufficient marks to show that it is apparent only, and 

 that the real evolution and position of them is that of 

 their type, the leaf. 



