BRITISH CHAROPHYTA. 



size (Fig. 9 i). In other cases there is a varying dis- 

 parity, in some species the cells of the primary 

 (Fig. 9 ii, iii) and in others those of the secondary 

 (Fig. 9 iv) being the larger. 



In a third type of cortex, found in a very few 

 species, no portions of the cortical node-cell are cut 

 off at the sides, therefore no secondary cortical-cells 

 are present. The cortex is then styled HAPLOSTICHOUS, 

 there being only one row of cortical-cells to each 



in 



n 



. 9. Transverse sections of stems showing various types of cortex 

 of Chara. Triplostichous : i. Isostichous C. fragilis ; ii. Aniso- 

 stichous C. delicatula. Diplostichous : iii. Tylacanthotis C. bal- 

 tica; iv. Aulacanthous C. rudis. In ii and iii spine-cells are shown 

 to indicate primary cortical rows. Haplostichous : v. Contiguous 

 C. canescens ; vi. Non-contignous C. imperfecta. 



branchlet (Figs. 8 iii, 9 v, vi). The cortical-rows 

 may be contiguous (Figs. 8 iii, 9 v) or non-contiguous 

 (Fig. 9 vi). 



The second direction in which division takes place 

 in the node- cells of the cortex is by the cutting off of 

 a portion from the outer side of the periphery, that is 

 the side farthest from the axis of the stem. The 

 result of this is the production of outward free- 



