ITS GENERAL MORPHOLOGY. 237 



common type, only differing in their special development. And it 

 may be added, that in an early stage of development they all ap- 

 pear alike. That which, under the ordinary laws of vegetation, 

 would have developed as a leafy branch, does, in a special case 

 and according to some regular law, finally develope as a flower ; 

 its several organs appearing under forms, some of them slightly 

 and others extremely different in aspect and in office from the fo- 

 liage. But they all have a common nature and a common origin, 

 or, in other words, are homologous parts (424). They all answer 

 respectively to the leaf part of successive phytons. 



434. Now, as we have no general name to comprehend all 

 those organs which, as leaves, bud-scales, bracts, sepals, petals, 

 stamens, &c., successively spring from the ascending axis or stem, 

 having ascertained their essential identity, we naturally, and in- 

 deed necessarily, take some one of them as the type, and view the 

 others as modifications or metamorphoses of it. The leaf is the 

 form which earliest appears, and is the most general of all the or- 

 gans of the vegetable ; it is the form which is indispensable to 

 vegetation in its perfected development, in which it plays, as we 

 have seen, the most important part ; it is the form into which all 

 the floral organs may sometimes be traced back by numerous 

 gradations, and to which they are liable to revert when flowering 

 is disturbed and the proper vegetative forces again prevail. Hence 

 the leaf may be properly assumed as the type or pattern, to which 

 all the others are to be referred. When, therefore, the floral or- 

 gans are called modified or metamorphosed leaves (terms which we 

 have avoided almost entirely, as liable to convey an erroneous im- 

 pression), it is not to be supposed that a petal has ever actually 

 been a green leaf, and has subsequently assumed a more delicate 

 texture and hue, or that stamens and pistils have previously existed 

 in the state of foliage ; but only that what is fundamentally one 

 and the same organ developes, in the progressive evolution of the 

 plant, under each or any of these various forms. When the indi- 

 vidual organ has once fairly begun to develope, its destiny is fixed. 



435. The theory of vegetable morphology may be expressed in 

 other, and more hypothetical or transcendental forms. We have 

 preferred to enunciate it in the simplest and most general terms. 

 But, under whatever particular formula expressed, its adoption has 

 not only greatly simplified, but has thrown a flood of light over the 

 whole of Structural Botany, and has consequently placed the 



