24 



BRITISH CHAEOPHYTA. 



The stem-node consists in the first place of a single 

 disc-shaped or biconcave cell, which is capable of 

 division to an indefinite extent. The peripheral cells 

 resulting from the division give rise to certain lateral 

 outgrowths which will be dealt with in turn. The 



Fia. 5. — Axial section of shoot of Chara (after Sachs) . A. Apical cell 

 of main axis. n. Central cells of stem-node. i. Internodal cells of 

 main axis. s. Stipulodes. c. Cortex of stem. bk. Branchlets : a, 

 apical cell ; n, central cells of node ; i, internodal cells ; c, cortical 

 cells ; d, bract-cells. ? . Oogonia. S . Antheridia. B. Young 

 branch ; the parts of this are similar to those of the main axis. 



earlier stages of division, which are longitudinal in 

 the direction of the axis of the stem, are shown in 

 Fig. 4 (p. 23), the order in which the several cells 

 originate being very similar to that of the pro- 

 embryonic whorl-node already referred to. 



