44 



BRITISH CHAROPHYTA. 



In Lychnothamnus and Nitellopsis the arrangement 

 is apparently similar. In Lychnothamnus the oogonium, 

 which is solitary, is produced separately from the 

 central peripheral cell on the inner side of the 

 branchlet, that is the side facing the stem or branch, 

 and antheridia are normally produced from peripheral 

 cells on either side of that producing the oogonium 

 (Fig. 16 iii A and B). In Nitellopsis the only known 



Pig. 16. — Position of reproductive organs in several genera. <J = 

 antheridium, ? = oogonium in all figvires. i. Nitella flexilis (after 

 Sachs) : pr, apex of primary ray ; sr, bases of two secondary 

 rays. ii. Tolypella glomerata (after Migula) : pr^ primary ray ; 

 sr, secondary lateral rays ; tr, terminal ray. iii. Lychnothamnus 

 barbatus (after Braun) : A. Side view. b. Transverse section of 

 branchlet-node (schematic) — n, central cell of node ; he, bract-ceUs. 

 iv. Lamprothamnium papulosum (after Braun) : A. Vertical section 

 of branchlet-node. b. Transverse ditto — n, central cell of node; 

 pc, peripheral cells of node ; be, bract-cells ; i, intemodal cells of 

 branchlet J a, antheridium. 



species is dioecious so that the relative position of 

 the two organs cannot be ascertained, but their origin 

 appears to be similar to that in Lychnothamnus. 



In Lamprothamnium and Chara, which in the position 

 of their reproductive organs are somewhat similar. 



