108 



MANUAL OF BOTANY 



of them. This sprmgs from the air-chamber layer, but thins 

 out as it grows, forming a membranous structure which is very 

 much dissected or lobed. Besides this perichaetium, another 

 membrane, the ^erigynium, grows up from the base of each 



Fig. 867. 



Fig. 867. Archegoniopliore of Marchantia, bearing archegonia on under sur- 

 face. 2, 3, 4, 5, 9, 10, 11. Successive stages in development of archegonia. 

 14. Root hair with characteristic tliickeiiiiig nn the walls. After Kiiy. 



archegonium itself, surrounding it as a kind of open sac as it 

 approaches maturity. 



Both the antheridiophore and the archegoniophore are com- 

 pound, being composed of two coherent branches, the ventral sur- 

 faces of which are consequently internal, From these ventral suy- 



