CRYPTOGAMS 



203 



have water only when dew or rain falls. Other kinds live 

 in the crevices of bark on tree trunks ; others on soil. The 

 Sphagnum Mosses live in bogs, of which they sometimes 

 form the chief vegetation. Peat from 

 these bogs (used for fuel in some coun- 

 tries) is to a considerable extent made 

 up of the dead stems and leaves of these 

 Mosses. 



474. Reproduction is essentially the same 

 in Mosses as in Liverworts. On the end 

 of the stem, usually, 

 at the proper sea- 

 son archegonia (Fig. 

 341) are found. An- 

 theridia (Fig. 342) 

 arise in a similar 



341. 



position ; but in 

 most species the 

 two kinds of or- 



(/) on the end of a gans OCCUr on dif- 

 Moss stem. j? i mi 



terent snoots. Ine 



342. Group of antheridia : (a) 

 and sterile filaments 



Archegonium 

 of a Moss : 

 e, egg cell; 

 n, neck; I, 

 lid (opening 

 before fertil- 

 ization) . 

 SACHS. 



antlierozoid is motile by means of two cilia, and reaches 

 the archegonium and finally the egg cell when the plants 

 are wet. Fertilization 

 results, as in Liverworts, 

 in the production of a 

 (usually long - stalked) 

 sporogonium (Fig. 340). 

 The upper part of the old 

 archegonium may be car- 

 ried up on the growing 

 sporogonium as a cap 

 (calyptra, c). The spore 

 capsule opens for libera- 

 tion of the spores by the 



displacement of a lid (operculum, o) in most Mosses. 



475. When the spore germinates it gives rise, not to the 



Moss shoot directly, but to a many-branched filamentous 



343. Protonemaof Moss: b, bud of Moss 

 shoot. FRANK. 



