THE ANGIOSPERMS 



265 



tion should be given not so much to collecting specimens for 

 identification, but to seeking illustrations of the principles of 

 adaptation they have studied earlier in the course. Practi- 



UNICELlLULAR 



FLAGBELLATE 

 GREEN 1 ALGAE 



FIG. 29. Hypothetical tree of relationship and descent of the leading 



groups of plants. 



cally, I have found that large field parties are not profitable, 

 and that ten is a maximum number that should be allowed 



