MUSCI AND HEPATICAE 



359 



besides this, in many Mosses certain parts are so developed during 

 normal life that they are readily detached as gemmae, which may start 

 new colonies in fresh stations. The protonema itself may break into 

 short lengths (Funaria), or bulbils may be formed upon it (Barbula) 

 (Fig. 297, B), or gemmae may be formed on the surface or the leaves 

 (Grimmia), or in terminal cups (Tetraphis). Or whole leaves, slightly 



FIG. 301. 



Leaf gemmae of Aulacomnion palustre. 

 The drawing shows the gemmae, and scars 

 where some have been shed. 



FIG. 302. 



Meesia uliginosa, Hedw. (After 

 Hedwig, 1787.) Showing antheridia 

 (an), and archegonia (ar), withfpara- 

 physes (p), on same axis. 



modified for the purpose, may be detached, as in Aulacomnion palustre 

 (Fig. 301). In any case protonema is formed first, and subsequently 

 Moss-Plants. 



Frequently it is by such means that Mosses are spread. But a more 

 certain transfer to longer distances is by the minute spores produced 

 in the capsule, or sporogonium, which thus reveals itself as the sporo- 

 phyte generation (Fig. 296). This like other sporophytes results from 

 propagation by sexual organs borne by the gametophyte. The 

 antheridia and archegonia of Mosses are similar in essentials to those 

 of Pteridophytes, but different in details. They are sometimes borne 

 on the ends of the main stem (acrocarpic), sometimes on short 

 lateral branches (pleurocarpic), and this character is useful in the 



