eaunkiaer's life forms 29 



only for general comparisons; these may be subdivided when 

 necessary, and I have decided upon six ''size-classes" proceed- 

 ing from the smallest to the largest blade, and have given the 

 following names which may be used as adjectives as well as 

 nouns: Leptophyll, Nanophyll, Microphyll, Mesophyll, Macro- 

 phyll, and Megaphyll. 



In determining the limits of a single class I took a progressive 

 series of dry leaves varying much in size, and separated them 

 tentatively into six classes. I placed them upon millimeter 

 paper and carefully noted where the boundary between the 

 six classes could be set. I also persuaded a number of botanists 

 among my colleagues to consider the same problem. The re- 

 sult has caused me to set the upper limits of the lowest "size- 

 class," Leptophylls, at 25 square millimeters. Five consecu- 

 tive multiplications by 9 give products that respectively cover 

 all the material. The limits between the various classes are 

 represented accordingly: 



Originally I multiplied by 10, but the resulting limits between 

 the "size-classes" did not seem as natural as when 9 was used. 

 It is easy in the final analyses to separate the single classes into 

 the groups of small, medium, and large. As shown by the dia- 

 grams (fig. 1) I have produced a graphical scheme whereby the 

 leaf-size is indicated as well as the limit between the different 

 classes. The leaf blade which is smaller than figure a (25 sq. 

 mm.) is a leptophyll; that which lies between figures a and b 

 (9 X 25 sq. mm.) a nanophyll; between b and c (9- X 25 sq. mm.) 

 microphyll. The size represented by the limits between n ac- 

 rophyll and megaphyll gives a dimension that is practically 8 

 times the size of the entire figure. 



Usually, by a comparison with these standards, it will be an 

 easy matter to determine the class to which a certain leaf be- 



ARY. 



/</ 



'.^^ 



