94 STUDY OF COMMON PLANTS. 



artificial, aud that their value is rather that of convenience 

 than as an expression of relationship. Nevertheless it is 

 oiasaifioation. the case many times that in a given group of 

 Moa™d''b" Pl'^i^ts ^ certain kind of fruit prevails, not in- 

 fraits. frequently to the exclusion of all other kinds. 



Thus the pepo is the fruit of the gourd family, the ache- 

 nium of the composites, and so on, so that by means of the 

 fruit alone it is often possible to determine the relation- 

 ship of the plant from which it came. Accordingly the 

 student is advised to familiarize himself with the various 

 kinds of fruits by a careful study and classification of such 

 a collection as that of the list in this exercise, and in his 

 subsequent study of special groups of plants to observe 

 how far the kind of fruit is characteristic. Such a mode of 

 procedure will give interest and meaning to what other- 

 wise is likely to be nothing more than a Mte noire to the 

 beginner. 



In closing our study of fruits we come back again to the 

 seed, with which we started, and it must already have oc- 

 Cyolo of de- curred to those who are in the habit of stopping 

 flowerks*" *'° think, that the same plant appears at differ- 

 piants. ent periods .of its life under widely different 



forms. The seed represents the plant in its period of rest, 

 but it is as truly the plant in this state as in its nfciod of 

 highest activity. We may even hold, perhaps more accu- 

 rately, that a part of the seed — the embryo — -strictly rep- 

 resents the entire plant, the parts around the embryo being 

 merely protective or food-supplying accessories that belong 

 in reality to the preceding generation. ^ We have found it 

 best to study parts of many different species in order to 



1 The theory of the alternation of generations and the details of 

 the reproductive process cannot well be discussed until the student is 

 acquainted with flowerless plants. 



