202 



CItVPTOGAMS 



339. A foliose Liverwort. 



however, the archegonium appears in all the cryptogamic 

 forms, and even in the Gymnospernis 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 bod}'. 



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

 Marcliantia. Tlie archegouia and antheridia are borne by the thallus 



without the forma- 

 tion of special erect 

 .- brandies. The 

 structureof thespo- 

 log'oniura (spore- 

 bearing body) dif- 

 fers widely in other 

 members of the 

 group also. Many 

 of the species — e.;/. many small forms found on tree trunks — show a 

 distinction of stem and leaf (Fig. 3:j9). 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. Tlie 

 foliose (leafy) Liverworts might indeed at a casual glance 

 be mistaken for ]\Iosses. In tlie latter, however, the 

 leaves are generally arranged 



radially about the stem (Fig. 

 '^AO ) ; wliile in tlie foliose Liver- 

 worts, as seen from Fig. fj?>'.\ 

 the leaves are so disjjosed that 

 the whole shoot has a flattened 

 character in accordance with 

 the creeping habit. 



473. The flosses live in 

 very diverse sitnations. Some 

 common species gi'ow wbollv 

 snlmierged in running water 

 like Alg:e. Again, many com- 

 mon species inhaliit extremely 

 dry places, like the bare face 

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

 lected b}' the Mosses themselves, and where the plants can 



340. 



A Moss shoot after the pro- 

 duction of a sporoj^onium : 

 5, spore capsule; o, opercu- 

 lum; c, calyptra. 



