34 



BRITISH CHAROPHTTA. 



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 secondar'y cortical-cells 

 are present. The cortex is then styled Haplostichous, 

 there being only one row of cortical-cells to each 



III 



II 



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

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

 stichous — 0. ddicatula. Diplostichous : iii. Tylacanthous — C. bal- 

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

 to indicate primary cortical rows. Haplostichous : v. Contiguous 

 — C. canescens ; vi. Non-contiguous — 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- 



