ECOLOGY OF SHOOT AND ROOT 2O/ 



so much less marked than in tropical and desert plants, 

 that it will be necessary to use some of the latter in order 

 to give anything like an adequate view of the subject. The 

 teacher must then supply data as to their habits, describing 

 the characters of the desert, the tropical jungles, etc., illustrat- 

 ing by photographs as fully as possible. The teacher must 

 carefully guard against dogmatism in ecology ; at the best this 

 division of the science is at present in a very new and 

 undifferentiated state, and even among specialists much of it 

 is but guesswork. A complete study of this subject involves 

 also an examination of the texture, or tissues ; for adaptation 

 shows itself in minutiae as well as in large features, in the 

 suppression of some tissues and excessive development of 

 others ; but this work is hardly practicable in an elementary 

 course, except very superficially. 



In this connection the teacher should give fully illustrated 

 lectures or talks upon the very important and interesting 

 subject of the ecological groups of plants, the Mesophytes, 

 Halophytes, etc. These groups may be classified thus, follow- 

 ing Warming : 



A. Groups in adaptation to physical conditions. 



1. Mesophytes, Normal Plants. 

 (Trophophytes, those with winter defoliation. 

 Schimper.) 



2. Xerophytes, Desert Plants. 



3. Halophytes, Strand Plants. 



4. Hydrophytes, Water Plants. 



B. Groups in ndaptation to other organisms. 



5. Climbers. 9. Insectivora. 



6. Epiphytes. 10. Myrmecophila. 



7. Saprophytes. n. Symbionta. 



8. Parasites. 



