SUMMARY AND CONCLUSION 297 



deciduous leaves and winter buds of the woody plants 

 of cold regions are, with little question, adaptations of 

 a similar nature. 



Normal green plants alone are capable of utilizing the 

 carbon dioxide of the atmosphere, and those plants 

 which have no chlorophyll must depend upon either 

 living or dead organic matter for their carbonaceous 

 food. Among the flowering plants, at least, these 

 parasites, or saprophytes, are always evidently related 

 to normal green forms, and are unquestionably second- 

 ary forms which are descended from chlorophyll-bearing 

 plants. These parasites always show evidences of more 

 or less profound degeneration, the leaves and roots usu- 

 ally being rudimentary, and the floral parts often shar- 

 ing in this degeneration. This degradation of the 

 reproductive parts in parasitic and saprophytic plants 

 is especially noticeable in fungi, where in many in- 

 stances all traces of the sexual reproductive parts are 

 apparently lost. Among the flowering plants, the seeds 

 of such forms are often very small and the embryo 

 rudimentary. 



Since light is of the first importance to all plants 

 possessing chlorophyll, many adaptations are associated 

 with this. Epiphytes and climbing plants of various 

 kinds have developed their special habits of growth in 

 response to the need of light. So also the development 

 of special pigments associated with the chlorophyll is, 

 in most cases, to be explained as being concerned with 

 the question of light. 



In short, we find that plants have succeeded in adapt- 

 ing themselves to almost every environment. From 

 the open ocean to arid deserts and lofty mountain tops 



