ANATOMY AND MORPHOLOGY OF THE FLOWER 239 



The following principles should be observed in their con- 

 struction. The two kinds are complementary to one another, 

 and it is not necessary to try to show in one what is already 

 brought out in the other. Relations of number, alternation 

 and coalescence of like parts, are brought out in the horizontal, 

 and general form and adnation of unlike parts in the vertical. 

 Conventional signs, as shown by the accompanying examples, 

 can be used for the parts. Form should be shown only so 

 far as possible without interfering with the clearness of repre- 



FlG. 25. Diagrams of Scilla flower. Receptacle dotted; carpels cross- 

 lined ; petals black ; sepals and stamens unshaded. 



sentation of the more essential features. They should be 

 constructed with the most rigid exactness, every spot and 

 line having its meaning, and no confusion of lines allowed. 

 Particularly important is the insertion of parts upon the re- 

 ceptacle and upon one another ; and lines should not be 

 allowed to touch one another in the diagram except in 

 order to represent parts grown together in the flower. 

 The help of compasses, etc., should be required, if necessary, 

 to make them symmetrical. Teachers should remember, how- 



