64 PLANT LIFE. 



plant life just enumerated are not absolutely restricted to 

 members of the Vegetable Kingdom. All three are met with 

 in certain of the lower but unmistakable members of the 

 Animal Kingdom ; but while in the last-named group these 

 features are most pronounced low down in the scale of dif- 

 ferentiation of animal life, and completely arrested and 

 superseded as development proceeds, in the plant world, on 

 the other hand, these same structures become more and 

 more specialized, and the whole structure of the vegetative 

 parts of plants in general is so arranged as to facilitate the 

 working of the chlorophyll, as illustrated by the flattening out 

 of the substance of the plant into thin plates — leaves — for 

 the purpose of exposing a great area of chlorophyll-bearing 

 surface. In the case of many simple forms of animal life, 

 that were at one time supposed to possess the power of 

 forming chlorophyll, it has been shown that the chlorophyll 

 belongs to minute algse, that are incorporated in the soft 

 substance of the animal ; yet there are cases where animals 

 appear in reality to possess the power of developing chloro- 

 phyll. In Fungi and some flowering plants chlorophyll 

 is entirely absent ; but in all such cases the plants at present 

 without chlorophyll have degenerated from chlorophyll- 

 producing ancestors. Starch is found in many, even if not 

 in all, of the uncoloured forms of the Protozoa, a primitive 

 group of animals, according to Biitschli. 



In the simplest and most primitive of known plant forms, 

 met with at the starting-point of the algse, the mode of 

 reproduction is asexual or vegetative, usually effected by 

 division or fission of the generally unicellular organism. In 

 such cases it will be observed that there is no definite pro- 

 vision for death ; in other words, no provision, as in the higher 

 forms of life, for the return of the mass of material appro- 



