124 MOSSES AND LIVERWORTS 



fertilising organ (antheridium] of the Blunt-leaved 

 Bog-moss (Sphagnum cymUfolium) has been drawn 

 side by side with one from the Whitish Liverwort 

 (Diplophyllum albicans). 



The Fruit-bearing Organ (archegonium) corre- 

 sponds much more closely in appearance with the 

 same organ in a moss, having a more or less 

 distinct neck, which ends in a round, swollen 

 base. Plate IX. fig. 8 gives a group of three, 

 not quite fully developed, while at fig. 7 is one 

 which has arrived at maturity. Here again it 

 must be borne in mind that my drawings are 

 some fifty-one times larger than the original 

 objects. There is one feature in connection with 

 the position of the fruit-bearing organs in which 

 the liverworts differ very materially from the 

 mosses. We have seen (p. 35) that in the mosses 

 the fruit-bearing organs are generally surrounded 

 by a number of special leaves (the perichcetial 

 leaves), which, as a rule, are larger than, and 

 differ in shape from, the ordinary leaves of the 

 plant ; these special leaves, in addition to forming 

 a protective covering to the reproductive organs, 

 are of great assistance in retaining round them 

 the water that is so essential if fertilisation is to 

 be effected. In most of the leafy liverworts the 

 fruit-bearing organs (and sometimes the fertilising 

 organs also), instead of being enclosed in these 

 large, protecting leaves, are produced inside a 

 leafy, cup-shaped growth, such as that given at 



