202 



CRYPTOGAMS 



however, the archegonium appears in all the cryptogamic 

 forms, and even in the Gymnosperms among Flowering 

 Plants. In Liverworts and all plants higher in the vege- 

 table series the fertilized egg cell germinates in position, 

 and develops to a spore-bearing body. 



471. Other Liverworts. Some of the Liverworts are simpler than 

 Marchantia. The archegonia and antheridia are borne by the thallus 



without the forma- 

 tion of special erect 

 branches. The 

 structure of the spo- 

 rogonium (spore- 

 bearing body) dif- 

 fers widely in other 

 339. A foliose Liverwort. members of the 



group also. Many 



of the species e.g. many small forms found on tree trunks show a 

 distinction of stem and leaf (Fig. 339). Between thalloid and leafy 

 forms gradations are found. The essential structure of archegonium 

 and antheridium is the same throughout the group. 



472. Mosses are closely related to the Liverworts. The 

 foliose (leafy) Liverworts might indeed at a casual glance 

 be mistaken for Mosses. In the latter, however, the 

 leaves are generally arranged 



radially about the stem (Fig. 

 340) ; while in the foliose Liver- 

 worts, as seen from Fig. 339, 

 the leaves are so disposed that 

 the whole shoot has a flattened 

 character in accordance with 

 the creeping habit. 



473. The Mosses live in 

 ver}' diverse situations. Some 

 common species grow wholly 

 submerged in running water 

 like Algae. Again, many com- 

 mon species inhabit extremely 

 dry places, like the bare face 



of rocks, where there is no soil but dust and debris col- 

 lected by the Mosses themselves, and where the plants can 



340. A Moss shoot after the pro- 

 duction of a sporogonium : 

 s, spore capsule ; o, opercu- 

 lum ; c, calyptra. 



