BEYOPHYTA— MUSCI 



115 



Fig. 873. 



spiral thickenings ; others, which form a network between the 

 large ones, are small and tubular and contain chloroplastids. 



The antheridia and arclie- 

 gonia are usuall}' borne amid 

 clusters of leaves at the apex of 

 a shoot. Most generally there 

 are several together, though this 

 is not always the case. Some- 

 times a shoot bears only an- 

 theridia, sometimes only arche- 

 gonia, sometimes archegonia in 

 the centre of the sorus or collec- 

 tion, and antheridia around the 

 periphery. AVe may thus have 

 moncecious, dioecious, or herma- 

 phrodite arrangement. 



The sorus is invested with 

 leaves of rather different cha- 

 racter from the ordinary foUage 



Fig. 873. Leaf of Sphagnum. A. Sur- 

 face view. B. Section. 



spar. 



ant. 



Fi<j. 874. Apex of fertile shoot of 'Sloss, {Poly trick nm) bearing antheridia, 

 ■ ant, and paraphyses, j^f^i'- ?• Leaves of the shoot. 



leaves ; the innermost of them at any rate growing up in a sort 

 of perichsetial fashion round the base of the capsule as it begins 



t2 



