LESSONS ON PLANT FAMILIES. 



CHAPTER XXXVI. 



RELATIONSHIPS SHOWN BY FLOWER AND FRUIT. 



480. Importance of the flower in showing kinships among 

 the higher plants. In the seed-bearing plants which we are now 

 studying \ve cannot fail to be impressed with the general pres- 

 ence of what is called the flower, and that the flower has its culmi- 

 nating series in the spore-bearing members of the plant (stamens 

 and carpels). Aside from the very interesting comparison of the 

 changes which have taken place in passing from the simple and 

 generalized sporophyte of the liverworts and mosses to the com- 

 plex and specialized sporophyte of the higher plants, we should 

 now seek to interpret the various kinds of aggregations of the 

 spore-bearing members, here termed stamens and carpels. In 

 the part of the book which deals with ecology we shall see how 

 the grouping of these members of the plant is an advantage to it 

 in the performance of those functions necessary for fruition. 



481. While the spore-bearing members, as well as the floral 

 envelopes, are thus grouped into " flowers," there is a great 

 diversity in the number, arrangement, and interrelation of these 

 members, as is suggested by our study of trillium and dentaria. 

 And a farther examination of the flowers of different plants would 

 reveal a surprising variety of plans. Nevertheless, if we com- 

 pare the flower of trillium with that of a lily for example, or the 

 flower 01 dentaria with that of the bitter-cress (cardamine), we 

 shall at once be struck with the similarity in the plan of the 



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