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 
