INTRODUCTION. 9 



of laboratory drawing is not likely to be too strenuously 

 urged, and the difficulty and tediousness of execution, 

 which will largely disappear with practice, should never 

 be offered as an excuse for its neglect. 



Drawings may represent the object with various degrees 

 of completeness. At one extreme is the diagram, which 

 aims only to give relative positions, sizes, and relations 

 of parts. A diagram is often very helpful at the begin- 

 ning of the study of a specimen. At the other extreme 

 is the drawing that is as close a counterpart of the object 

 seen as the person who draws it is capable of producing. 



Drawings may usually be made satisfactorily in out- 

 line with but little shading. The best results may be 

 obtained by making definite outlines first by use of a 

 sharp, hard pencil, then tracing the outlines and shading 

 with a fine pen and good ink. The paper used for draw- 

 ing should be the heaviest linen ledger-paper or (more ex- 

 pensive) bristol-board. A convenient form is had by 

 cutting the paper into pieces four by six inches. Note- 

 paper may be cut of the same size, and the two may be 

 bound temporarily, thus constituting a book to which 

 the student adds at each laboratory period. Such blank 

 laboratory books are sold by reliable dealers. 



The approximate amount of magnification, if any, under 

 which the specimen was observed at the time the drawing 

 was made should always be noted in connection with the 

 figure. 



Photographs may be useful in illustrating habitats and 

 individual characteristics of plants not readily observed by 

 the class. Both geographical and seasonal distribution 

 of plant life is such that often it is impossible for students 



