GENERAL MORPHOLOGY OF THE PLANT 9 



arranged in strings or filaments ; in others tliey form flat plates ; 

 in yet others they constitute masses of great size and much- 

 divided shape. The plant body, in the latter ease, is evidently 

 segmented into parts, which are spoken of as its members. 



The study of the life history of most plants shows us further 

 that each may have different forms at different periods of its life. 

 Inmanyof thelowerplants this^jo%i»o)7)%,as itiscalled,is very 

 varied ; but as the organism studied is higher in the scale, it is 



Fig. 14. 



F/V. 14. A Tree Tevn. 



found there is a tendency to assume only two forms, which recur 

 in constant alternation with each other. Each form is character- 

 ised by producing special kinds of reproductive organs, and bears 

 a name indicating their nature. The common Fern is perhaps the 

 most easily studied illustration of this. In the form unusuallj- 

 recognised as the Pern plant, the plant body is found to carry 

 out the process of reproduction by certain cells which are known 

 as spores. These are asexual reproductive cells, that is, each is 

 capable by itself of producing a new individual. This form, as 



