BOTANY OF THE LIVING PLANT 



Highly magnified, the powder is seen to consist of single spherical 

 cells, or groups of cells (Fig. i). Each of these cells is an individual 

 Plant, and it multiplies by division. The results of such repeated 

 divisions may remain for a time coherent, thus forming groups of 



varying number. But finally they 

 separate, and each single cell can con- 

 tinue its life as a distinct unicellular 

 organism. It is called Protococcus, 

 a name which recognises its simple 

 primitive nature. It would be held 

 as taking a low place in the scale of 

 vegetation, and would be classified 

 near to the beginning of our Series. 



On the other hand, ordinary herbs, 

 shrubs and trees are examples of more 

 elaborate organisation. Each one of 

 these is composed of various large and 

 complex parts, which are united to 

 form the complete Plant, and severally 

 serve distinct functions for the benefit 

 of the whole. Such Plants may at- 

 tain large size, and very complicated 



structure, as in the case of Forest Trees (Frontispiece). Each of these 

 Plants is. an independent individual. Their increase in number is 

 by Seeds, produced through the process of Flowering. The pro- 

 duction of seed is an involved and elaborate process, as will be seen 

 when it is described in later chapters. Partly on the ground of 

 their complex structure, and partly because of the elaborate method 

 of their propagation, such Flowering Plants, or Seed-Plants, are ranked 

 as higher in the scale. Between such extremes as Protococcus and a 

 Flowering Plant other intermediate types may be ranked according 

 to their structure and their method of increase. And so a Series 

 may be formed leading from those which are comparatively simple, 

 by gradual steps, to those which are more elaborate. Such a Series 

 is believed to illustrate roughly, and with some degree of truth, the 

 course which the Evolution of the Vegetable Kingdom has actually 

 followed. The simpler examples are held to represent such types as 

 appeared earlier in the History of Descent, and thus to be more 

 primitive. The types which are more complex in structure, and in 

 their method of propagation, are believed to have appeared later in 

 the History of Descent, and are regarded as derivative. This agrees 



FIG. i. 



Cells of Protococcus, some isolated, 

 others, resulting from recent division, are 

 still coherent. (X730.) 



