166 



BRYOPHYTES 



There are two large groups of mosses, the Bryales, which 

 we have just described and the Sphagnales. This latter group 

 is the characteristic moss of the sphagnum swamps and was the 

 most important group of plants in the formation of peat and 

 coal beds. 



The Hepaticae or liverworts are not so familiar to most 

 of us as are the mosses and ferns. They rank next below the 

 mosses and are an extremely interesting group for study, but of 

 very little, if any, economic value. There .are several divisions 

 of the hepaticae, but one of the largest and most common forms 



FIG. 105 Fia. 106 FIG. 107 



FIG. 105 Marchantia polymorpha showing two cupules bearing gemmule. 



Fio. 106. Surface view of marchantia polymorpha very much magnified. 



Fia. 107. a, female plant of marchantia polymorpha bearing two archegonial branches; 



I >, also a single antheridial branch from a male plant. 



is known as Marchantia polymorpha. (Fig. 105.) It reminds 

 us of the fern prothallus but is much larger and branching. It 

 is thick along its central axis and thin at the edges, lies flat on 

 the wet soil and has many rhizoids. The upper surface is 

 divided into small areas with a small opening (stoma) (Fig. 

 106) in the centre of each. These small areas give it a super- 

 ficial resemblance to the liver of an animal and therefore the 

 name " liverwort." As the apical part of the plant grows the 

 basal part is gradually dying. Along the upper surface will fre- 

 quently be found saucer-shaped structures containing small buds 

 which are capable of growing into new plants; a non-sexual 

 method of reproduction. 



