THE INFLORESCENCE, AND THE FLOWER 241 



Fay carrying this out. Seed- Plants are dcpouioi/ upon external a^emies, 

 such as luater, ivind, or animal activity. Moreover, as the IM.int is 

 fixed in the soil and immobile, such a^^encies must be resorted to if 

 the advantage of intercrossing is to be secured. It is such considera- 

 tions as these which make intelligible the varietv and intricacy of the 

 forms which Flowers show. 



The fact that the flower is constructed fundamentally on the same plan as 

 the foliage shoot did not escape the attention of the early botanists. More- 

 over, they noted that it is universally preceded by some form of vegetative 

 shoot in the individual life of the higher pkints. In annual plants this is 

 obvious enough : it is only after the establishment of the leafy plant that the 

 flower-buds make their appearance. But in the case of many of the plants 

 that expand their flowers in the early spring the matter is not so simple, and 

 one is apt to forget the swollen underground parts from whose stores the 

 flowers draw their material. It is needless to' elaborate by examples the 

 simple fact that in all cases nutrition must precede propagation. It was this 

 fact that formed the foundation of Goethe's theory of Metamorphosis. He 

 recognised under this name the process by which one and the same organ, for 

 instance the leaf, presents itself to us in various modifications, such as the 

 foliage leaf, sepal, petal, or stamen. He distinguished as " progressive meta- 

 morphosis " those changes of type of the appendages which proceed from the 

 cotyledons or seed-leaves, through the foliage region and bracts to the flower, 

 and finally to the perfected fruit. On the other hand he designatetl as " retro- 

 gressive metamorphosis " that process by which the succession appears 

 reversed ; as for instance in abnormal or doubled flowers, when a stamen or 

 a carpel develops as a petal, or even as a foliage leaf. These general ideas 

 of the relation of the vegetative and floral regions were amplified and made 

 more definite by later writers, and were for a long time widely held. Thus xt 

 became a general belief that the floiver had resulted from changes wrought in some 

 pre-existent vegetative shoot. 



So long as we direct our attention solely to the Flowering Plants this opinion 

 might stand. But as the nineteenth century drew on, knowledge of the lower 

 forms greatly increased, especially in the case of such plants as the Ferns and 

 Club-Mosses, This has supplied the material necessary for a revised theory of 

 the origin of the flower. Checked by theSe comparisons we may now figure, on 

 a basis of fact rather than of semi-poetical surmise, how the flower as distinct 

 from the vegetative region originated in the higher plants. The main point 

 to bear in mind is that the propagative function nuist have rcrurreil in each 

 fully completed life-cycle throughout descent. Hence the prcnluction of 

 sporangia was never an innovation, and they cannot at any time in the course 

 of descent have been imposed upon a pre-existent veget.it ive svstem. as 

 Goethe's theory would assume. The facts suggest that thf whole shoot of 

 relatively primitive Vascular Plants was vou-specialised. It served general 

 purposes, both for vegetation and propagation. But in the course of evolution of 

 higher types differentiation took place, so that a certain region became exclusively 

 vegetative, while another produced sporangia. Thus a theory of Skgreoation 

 takes the place of a theory of Metamorphosis. The vegetative phase naturally 



