V. 



MOSSES (MUSCI): SPHAGNALES—ANDREAiALES 163 



giving rise to a protonema upon which, as usual, the gameto- 

 phore arises as a bud. In size the gametophore of the Mosses 

 ranges from a milHmetre or less in height in Biixhaumia and 

 Ephcmeriim to 30 to 50 cm. in the large Polytrichacese and 

 Fontinalis. The branching of the gametophore is never 

 dichotomous, and so far as is known the lateral branches arise, 

 not in the axils of the leaves, but below them. Underground 



■'^- 



Fig. 86. — Climacium Americannm , showing the formation of stolons, X2« 



stems or stolons, which afterwards develop into normal leafy 

 axes, are common in many forms, e. g., Climacium (Fig. 86). 

 The sexual organs are borne either separately or together 

 at the summit of the gametophoric branches. WHiere the 

 plants are dioecious, it sometimes happens that the two sexes 

 do not grow near together, in which case, although archegonia 



