ACROGENS. 



Ill 



ary stem. The appendages are the leaves, branches, 

 rootlets, and reproductive organs. The points on the 

 axis, or stem, from which the appendages spring, are 

 called nodes, the intervening parts being the internodes. 

 In Chara the internodes have a spiral striation. Growth 

 takes place at the apex by the development of new 

 nodes and internodes. Each internode is formed by the 

 growth and elongation of one cell. 



The terminal bud is formed by a single cell, which di- 

 vides by fission into two, one of which forms the inter- 

 node, while the other sub- 

 divides into lateral cells, 

 which, by division, produce 

 the appendages. In the lat- 

 ter, after a certain stage, 

 the terminal cell is inca- 

 pable of further division, 

 but in the stem the proc- 

 ess continues indefinitely. 

 . 40.) 





FIG. 40. Growing Point of Chara. 

 The reproductive Organs <*. Terminal cell dividing, b. Cells form 

 , ing youngest node, and which by their fis. 



in these plants are Of tWO sion will give rise to a whorl of appendages. 

 i j i . c. c. Internodal cells, d. Incipient append- 



kinds, oval sporangia, or agss . ,. Same farther advanc ^ 

 spore-fruits, and antheridia. "ai ceil dividing. 

 The latter are smaller than the sporangia, and globular, 

 and contain filaments whose cells are changed into little 

 ciliated bodies called anther ozoids, (Fig. 41.) 



The growing spore from the sporangium gives off two 

 filaments resembling the hyphse in fungi, one of which 

 serves as a temporary root, and a cell in the other pro- 

 duces a group of lateral projections from which the young 



