EUPHYCOPHYTA 



117 



new apical cells, but these soon cease to grow after the branch has 

 reached a short length. At the basal node of the main plant branches 

 of unlimited growth are produced : these arise on the inner side of 

 the oldest lateral in the whorl, thus producing a fictitious appear- 

 ance of axillary branching. Multicellular branched rhizoids with 



Fig. 67 Charales. A, 1-6, successive stages in development of root 

 node of Chara aspera. A, double foot joint. 2, dilation of toe of 

 upper foot. 3, toe portion cut off. 4, 5, subdivision of toe cell. 6, 

 rhizoids growing out. B, 1-3, successive growth stages of apex of 

 Nitella. In i apical cell is undivided, in 2 it has divided, in 3 the 

 lower cell has divided into an upper node and a lower internode. 

 C, C. hispida, node with stipules. D, N. gracilis^ longitudinal sec- 

 tion of node. E, C fragilis, branch at node with axillary bud. a = 

 antheridium, ac= ascending corticating cells, as = apex of side 

 branch, bnl = basal node of branch (/), c and co = cortical cells, 

 d = descending cortical cells, i = internodal cell, n = nodal cell, 

 0= oogonium initial, s= stipule. (A, B, after Grove i C-E, after 



Fritsch.) 



oblique septa function as absorption organs and also serve for an- 

 chorage. The rhizoids develop from the lowest node of the main 

 axis, but every node is potentially capable of producing them though 

 normally the presence of the stem apex inhibits their appearance, 

 but if this is cut off they will then develop. This behaviour is very 

 suggestive of an auxin control similar to that found in the higher 



