PREFACE. V 



teacher of things which it is advisable to show to pupils under 

 the compound microscope, in case inadequate equipment, 

 lack of time, or difficulty of preparation forbid class study. 



I have made the directions fullest in relation to cryptogams 

 and physiology because these fields are most unfamiliar to 

 teachers at present. Further directions for the study of seed 

 plants can readily be provided from the books listed in Ap- 

 pendix IV. 



For laboratory study it is necessary to select certain illus- 

 trative types and observe their structure. In the text I have 

 not specifically discussed these plants, but have treated gen- 

 eral topics so as to correlate the facts gained by a study of 

 types with others which can be readily interpreted by means 

 of the experience in the laboratory. References from the 

 bare directions of Appendix I to the paragraphs and figures 

 of the text are abundant and are intended to aid the student 

 in the comprehension of the type under observation. It may 

 be objected that he is thus aided too much. But I believe 

 that in his first steps in laboratory training the student re- 

 quires a large amount of help, and that its results, are more 

 often nullified by too little assistance than by too much. 



In the text I have neither sought nor avoided the use of 

 technical terms. I have refrained from making the book a 

 mere illustrated glossary. Yet I see no advantage, even for 

 young students, in repeated circumlocution, for which a 

 single word might stand. Definitions of most of the tech- 

 nical terms used may be found by means of the index ; 

 others are defined in the standard dictionaries. The careful 

 teacher will insist upon a clear understanding of the meaning 

 of terms and the accurate use of language. 



I have refrained from frequent citation of plants by name 

 as examples of facts stated, chiefly because beginners are 

 rarely familiar with any plants except the commonest domes- 

 ticated ones and a few forest or shade trees. 



