THE BRYOPHYTA: MUSCI, THE MOSSES 



443 



CHLOROPHYLLOSE CELLS 



main stem produces a side shoot in its axil, which branches into a tuft 

 of three to six secondary branches, some of which stand upright, while 

 others are longer and pendant, 

 often clothing the stem thickly 

 and acting as water conductors. 

 Close to the apex the laterals 

 are short and stout, forming a 

 close, protective group around the 

 apical bud. These subsequently 

 lengthen and branch further, pass- 

 ing over into the condition of the 

 mature laterals described above. 

 Some of the upright branches 

 may enlarge till they equal the main stem, and being separated from it by 

 decay at the base, serve to multiply the plants vegetatively. 



NTERCELLULAR 

 OPENING 



Fig. 433. — Sphagnum cymbifolium. Transverse 

 section of leaf. {After Warnstorf.) 



Sexual Reproduction 



Sphagnum is sometimes monoecious and sometimes dioecious, that is, 

 the sexes are sometimes on the same plant and sometimes on different plants. 

 The male organs are borne singly in the axils of the leaves on special side 

 branches, which are stouter than the vegetative shoots and often different 

 in colour. Each antheridium is ovoid in shape and has a delicate stalk as 

 long as itself (Fig. 434). It opens apically, and the valves thus formed turn 

 backwards. It has been pointed out that the antheridia occupy the positions 



Fig. 434. — Sphagnum sp. Longitudinal section of an 

 antheridial branch showing stalked antheridia 

 axillary to leaves. 



