4 6 STRUCTURE OF SEED. [CHAP. 



to avoid them altogether. In order to understand the 

 structure of the seed, we must commence with the 

 flower, to which the seed owes its origin. Now I 

 have already mentioned, but it may be convenient to 

 repeat here, if you take such a flower as, say a 

 Geranium, you will find that it consists of the /bllowing 

 parts : Firstly, there is a whorl of greenjjeaves, known 

 as the sepals, and together forming the calyx 

 secondly, a whorl of coloured leaves, or petals, 

 generally forming the most conspicuous part of the 

 flower, and called the corolla ; thirdly, a whorl of 

 organs more or less like pins, which are called stamens, 

 in the heads, or anthers of which, the pollen is 

 produced. These anthers are in reality, as Goethe 

 showed, modified leaves ; in the so-called double 

 flowers, as, for instance, in our garden roses, they are 

 developed into coloured leaves like those of the corolla, 

 and monstrous flowers are not unfrequently met with, 

 in which the stamens are green leaves, more or less 

 resembling the ordinary leaves of the plant. Lastly, 

 in the centre of the flower is the pistil, which also is 

 theoretically to be considered as constituted of one or 

 more leaves, each of which is folded on itself, and 

 called a carpel. Sometimes there is only one carpel. 

 Generally the carpels have so completely lost the 

 appearance of leaves, that this explanation of their 

 true nature requires a considerable amount of faith, 

 though in others, as for instance in the Columbine 

 (Aquilegia), the original leaf-form can still be traced. 

 The base of the pistil is the ovary, composed, as I 

 have just mentioned, of one or more carpels, in which 

 the seeds are developed. I need hardly say that many 



