CONTENTS. 



PART IV : ECOLOGY. 



PAGE 



Chapter XIX. Forms of vegetation ..... 30S 



XX. Mesophytes ....... 312 



XXI. Xerophytes and iialophytes . . . 31S 

 XXII. Hydrophytes ....... 327 



XXIII. Adaptations to other plants as supports 330 



XXIV. Symbiosis 333 



XXV. Animals as food, foes, or friends . . 342 



XXVI. Protection and distribution of spores 



AND seeds ....... 352 



Appendix I. Directions for laboratory' study . . . 369 

 II. Directions for collecting and preserving 



material ........ 401 



III. Apparatus and reagents. .... 409 



IV. Reference books ...... 413 



V. Outline of classification . . . .415 



Index ............ 419 



