THE INFLORESCENCE, AND THE FLOWER 277 



which may be held as advances from a relatively primitive state, 

 where the fundamental number ruled through all the floral 

 whorls. 



The behaviour of the floral receptacle is biologically the most 

 important of all. Primitive flowers are hypogynous, exposing their 

 carpels on an elongated receptacle (Fig. 195). By shortening its 

 growth the epigynous state is produced (Figs. 177, 197), and the 

 carpels are immersed in the tissue of the axis. Thus they secure at 

 once the nursing advantages of additional protection, and of a near 

 relation of the ovules to the sources of supply. All the factors upon 

 which diversity of floral structure depends are biologically intelli- 

 gible. All lead to a higher probability of successful propagation. 

 It is, however, worthy of remark that the flower does not really 

 differ in respect of them from the foliage shoot : for all of the modifica- 

 tions can be matched by special instances of development in the 

 vegetative region. But features that are exceptional in the vegetative 

 shoot are common in the floral region, and it is that which makes 

 the structure of the flower seem peculiar. The real distinction 

 between the vegetative and the propagative shoot lies not in form, 

 or texture, or colour, or number or relation of the parts, but in the 

 fact that sporangia are present in the flower, while they are absent 

 from the foliage shoot. 



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 plants. 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 designated 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 it 



