VI PREFA CE. 



quainted with the haunts, the lives, the successes and faihires of 

 plants ; the influences of soil, moisture, and other environ- 

 mental conditions upon plants, and, what is also important, the 

 influence which plants exert upon their environment. Classes 

 may be taken into the field, at different seasons of the year, to 

 observe flower and bud formation, pollenation, seed production, 

 seed distribution, germination of seeds and nutrition of the 

 embryo, protection of plants against foes and extremes of 

 weather ; the relationships of plants in colonies, and their dis- 

 tribution in plant formations, etc. In all this study a knowl- 

 edge of some of the lower plants is important. 



It is not intended that the matter in the book should be mem- 

 orized for the purpose of recitations. It should be used as a 

 guide to the practical work, and as a reference book. The para- 

 graphs arranged in coarse print are intended in general to indi- 

 cate the studies whicli will serve as the basis for the practical 

 work by the student. In most cases the material for these 

 studies can be quite easily obtained and the laboratory work is 

 not difficult. The paragraphs in fine print are intended to fur- 

 ther illustrate the subject by discussion and illustration of the 

 more difficult phases of each topic. Some of these can be made 

 the basis for demonstrations by the teacher before the class, and 

 all will serve as a convenient means of getting at the important 

 reference matter by the student in a single book. Suggestions 

 on the study and the taking of notes, etc., by the student are 

 given in the appendix. 



Acknowledgments. — The author desires here to express his 

 gratefulness to liis associates in the botanical department of Cor- 

 nell University who have read the manuscript and have made 

 useful suggestions (Messrs. E. J. Durand, B. M. Duggar, K. M. 

 Wiegand, and Professor W. W. Rowlee). A'^aluable suggestions 

 were also given by Dr. J. C. Arthur, of Purdue University, who 

 kindly read the chapters on physiology, and by Professor W. F. 

 Ganong, of Smith College, who read some of the chapters on 

 ecology and the tables on the homologies of the gymnosperms 

 and angiosperms. 



