18 



ELEMENTARY STUDIES IN BOTANY 



plex, and therefore that there has been an evolution of re- 

 production. It must not be supposed that reproduction 

 always became more complex as a vegetative body became 

 more complex, for comparatively simple bodies may show 

 an advanced method of reproduction, and many complex 

 bodies have retained a relatively simple method of reproduc- 

 tion. In general, however, as plants advanced in the struct- 

 ure of their bodies, they advanced 

 also in the methods of reproduc- 

 tion. 



14. Vegetative multiplication. 

 - In the simplest plants, notably 

 the one-celled forms, new individ- 

 uals arise by dividing the old ones. 

 For example, a one-celled indi- 

 vidual works for a time as a vege- 

 tative body (engaged in the work 

 of nutrition), and then the cell 

 divides, producing two new indi- 

 viduals (Figs. 2 and 3). Since 

 this kind of reproduction involves 



only vegetative cells, it is called vegetative multiplication, 

 which means that it is simply a method of multiplying 

 vegetative cells. When these multiplied vegetative cells are 

 new individuals, the process becomes a kind of reproduction. 

 This seems to have been the first kind of reproduction 

 among plants, and in many groups it is still the only kind of 

 reproduction. Any group that has no other method of re- 

 production is regarded as one of very low rank, for the method 

 of reproduction among plants is regarded as more important 

 in ranking them than is the structure of their vegetative 

 bodies. 



It must not be supposed that vegetative multiplication 

 occurs only among the lowest plants, for it is found in all 

 groups of plants, even the highest. For example, when 



FIG. 13. Sargassum: fragment 

 of gulfweed, showing differen- 

 tiation of the body into stem, 

 leaves, and bladder-like floats 

 (resembling berries). 



