62 THE SECOND BOOK OF BOTANY. 



semblance of one plant to another is only the resem- 

 blance of one group of characters to another. Let 

 us make such a comparison between the buttercup 

 and columbine. 



Do not rely upon the descriptions in the book, 

 but make similar tables yourself. 



BUTTERCUP. Flower. 



Calyx. Sepals, 5, polysepa- 

 lous, inferior. 



Corolla. Petals, 5, polypeta- 

 lous, hypogynous, obcordate, 

 yellow. 



Stamens. o>, hypogynous. 



Pistil. Carpels, o>, apocar- 

 pous, superior. 



COLUMBINE. Flower. 



Calyx. Sepals, 5, polysepa- 

 lous, inferior, colored like 

 the petals. 



Corolla. Petals, 5, polypeta - 

 lous, hypogynous, spurred, 

 red. 



Stamens. oo, hypogynous. 



Pistil. Carpels, 5, apocar- 

 pous, superior. 



Comparing the above lists, you see agreements 

 and differences. The calyx and corolla of one plant 

 agree with those of the other in number of parts and 

 in the position of parts. They differ only in color 

 and outline. The stamens of one are like those of the 

 other in being numerous and hypogynous. The pis- 

 tils agree in structure, but differ in the number of 

 carpels. If you compare the leaves, stems, inflores- 

 cence, etc., you also get a list of their resemblances 

 and differences. This is comparing plants by the 

 groups of characters they present. 



These resemblances of character among plants are 

 called their affinities. 



The degree of affinity between plants depends 

 upon two circumstances: first, upon tho kind of 



