1048 



THE NATURE BOOK 



1 1 U « H \. 



THE RELATION BETWEEN THE PETALS AND THE STAMENS OF THE WATER LILY 



IS HERE WELL SHOWN. 



the stamens and pistil were developed 

 from the leaf in the first instance, the pro- 

 tecting calyx and the inner row of petals 

 coming later. If this argument be correct, 

 we should call the midway organs which 

 have been noticed in the Begonia and the 

 Water Lily as degenerate stamens rather 

 than as developing petals. 



The subject of the evolution of the 

 flower is a very profound one, and it is not 

 possible to do more than hint at the won- 

 derful process whereby the different parts 

 of the blossom have been developed. To 

 the general observer the most significant 

 point is the manner in which at every turn 

 one is brought face to face with the great 

 importance of the leaf in the economy of 

 the plant. It is in the leaf that the won- 

 derful manufacture of the life basis of the 

 plant — ^the green chlorophyll — takes place. 

 It is from the base of the leaf-stalk that 

 nearly all extensions of the plant arise. 

 Not a few plants are able to produce fresh 

 specimens on their foliage, whilst of course 

 many of the low forms of vegetable hfe 

 increase in no other way than by a system 

 of leaf extension. We shall not be far 

 wrong in regarding the leaf as the most 

 important organ of the plant. 



In considering the foregoing instance 

 the student can scarcely fail to have been 

 struck with the importance of those 

 examples which are in some way 

 de])artures from the normal. Certainly 

 it seems that as the great scheme of 

 evolution goes forward, the traces of the 



origin of things become less and less dis- 

 tinct. It \\all well repay anyone who is 

 interested in the subject to keep a sharp 

 look out for freak flowers, for, as we have 

 seen, it is most likely that in these forms 

 we shall find enlightenment as to the 

 beginnings of the floral organs. The 

 observer will find a much more fruitful 

 ground for observation in the garden or 

 greenhouse than out in the country. It 

 is a well-estabhshed fact that under 

 cultivation both animals and plants are 

 much more prone to vary than when they 

 are in a state of nature. We are not 

 very clear as to the reason for this ten- 

 dency, but the fact is beyond dispute. 

 One of the most remarkable cases which 

 has arisen as the result of cultivation, 

 having a bearing upon the evolution of 

 the flower, is the variety of Campanula 

 known as the " Cup and Saucer." As in 

 the case of the Gloxinia, which is 

 illustrated, the five united petals go to the 

 making of one bell, the five sepals being 

 more or less joined together, but, of course, 

 external to the corolla. In the form under 

 notice it is the joined petals which go to 

 the making of the cup, whilst the broad, 

 flattened-out, abnormal calyx is respon- 

 sible for the saucer. In this case the sepals 

 have lost their green tinting, and have 

 become blue or white as the colouring of 

 the corolla may be. These matters show 

 how im])ortant it is that the breeder of 

 new kinds of plants should be acquainted 

 with the scientific aspect of his work. 



