DEVELOPMENT AND FUNCTIONS OP CELLS. 



47 



already explained, the terminal cell containing the reproduc- 

 tive matter or spores. In Fig. 21, the Penioillum glaucum, 



Fig. 20. 



Fig. 21. 



another mould, we have a somewhat different arrangement of 

 the reproductive cells, which, instead of being inclosed in a 

 solitary terminal cell, are arranged side by side, forming a 

 number of beadlike branches at the summit of the stem. 

 These cells ultimately separate, and grow into new indi- 

 viduals. 



55. When plant-cells unite together permanently, as in the 

 bread-mould, their union with each other evidently corre- 

 sponds to the union of phytons on the stem of flowering- 

 plants, and forest-trees. It has been shown (p. 40) that a tree 

 "is not a simple individual, as is usually supposed, but a com- 

 munity of individuals." Every bud which develops into a 

 branch is in fact a phyton {^-tov, a plant), or new plant, and 

 is actually capable of becoming such when taken off from the 

 stem and introduced into the soil as a cutting. A tree is the 

 result of the evolution of a countless number of these super- 



