CHAPTER XV 



MORPHOLOGY, OR THE STUDY OF THE FORMS OF 

 PLANT MEMBERS 



208. Botanists interpret all parts of the plant in terms 

 of root, stem, and leaf. That is, the various parts, as 

 thorns, flowers, fruits, bud-scales, tendrils, and abnormal 

 or unusual members, are supposed to represent or to stand 

 in the place of roots, stems (branches), or leaves. 



209. The forms of the parts of plants are interesting, 

 therefore, in three ways: (1) merely as forms, which may 

 be named and described; (2) their relation to function, or 

 how they enable the part better to live and work; (.'>) their 

 origin, as to how they came to be and whether they have 

 been produced by the transformation of other parts. The 

 whole study of forms is known as morphology (literally, 

 the "science of tonus"). We may consider examples in 

 the study of morphology. 



2K). It is eustomary to say thai the various parts of 

 plants are transformed or modified root, stem, or leaf, bui 

 tli'- words transformation ami modification are nol used in 

 the literal sense. It is meant that the given part, as a ten- 

 dril, may occupy the place of or represent a leaf. It was 

 not firsl a leaf and then a tendril, bui was a tendril from 

 the firsl : the pari develops into a tendril instead of into r 

 leaf: it stands where a leaf normally mighl have stood. 



211. It is better to say thai parts which have similar 

 origin-, which arise from the same fundamental type, <>r 

 which are of close genealogical relationship, are homolo- 

 gous. Thus the tendril, in the instance assumed above, 

 i> homologous with ;i leaf. Parts which have Bimilar func- 



I L01) 



