2 SYSTEM A TIC PoMOTOC.Y 



relationships. It is now a^M-ccd tliat tlie best systems of classifi- 

 eation are tliose wliicli sliow natural affinities as opposed to 

 purely arbitrary methods which do not have in view the exj)res- 

 sion (if relationshii)s and that seek hut to name and plaee a 

 ])lant. One cannot wholly avoid ai'tifieiality, however, in sys- 

 tems which are natural. The classification of |)hnits to show 

 their natural rclat ioiisliijjs is also called hi.r<nt(niii/. 



2. Systematic pomology a means not an end. -Any system 

 of elassifyintr plants is hut a tem])ora ry arran<i'ement of j^roups 

 and individuals aecordinji; to the best knowledge of the time, 

 always with the reservation that when more is known the elassi- 

 fieation must be remade. In particular there ean never be a 

 permanent ideal elassifieation of fruits. Fruits are arranpfed 

 in a elassifieation with the aim of telling what is known about 

 groups so that the knowledge can be easily utilized by the 

 botanist, pomologist, plant-breeder, and fruit-grower. It does 

 not matter much that the systems of elassifieations of authors 

 seldom agree; in fact, it may be a distinct advantage for stu- 

 dents of fruits to see them through the eyes of different sys- 

 tematists. 



3. The proper concepts of plant groups. — The student of 

 systematic pomology must keep in mind that botanieal groups, 

 of which the species is the chief unit, are often arbitrary arti- 

 ficial creations to aid in the classification of plants in accordance 

 with the facts that have so far accumulated in regard to them. 

 Only such a conception can put pomology in its true light as a 

 branch of knowledge in process of evolution. Only so can it 

 be seen clearly that plants are continually changing, although 

 slowly. Any classification is but a picture of a bit of the 

 vegetable kingdom on a certain day, which at a future date 

 may not be a good picture. For later times there must be new 

 pictures to show the changes that are taking place. 



4. Descriptive pomology defined. — Descriptive Pomology is 

 the study of the form, features and structure of fruit-plants and 

 the relative disposition of their organs. In botany similar 

 studies are more often called structural hotany in which, how- 

 ever, the internal structure of the plant, as of cells, are subjects 

 of investigation; or, such studies may be called morphology 

 which differs, possibly, from structural botany in that the meta- 



