Ill 



MA RCHANTIEJE 



55 



In the simplest cases, where the archcgonia are borne upon 

 a receptacle ^ which is raised upon a stalk, e.g. Plagiochasma, 

 Clevea (Fig. i8, A), the receptacle does not represent, according 

 to Leitgeb,^ a complete branch, but is only a dorsal outgrowth 

 of the latter, which may grow out beyond it, or even form 

 several receptacles in succession. The first indication of the 

 receptacle is a dor- 



sal prominence which 

 soon becomes almost 

 hemispherical, and 

 near the hinder margin 



A. 



first 



archcgonium 



the 



arises, without, appar- 

 ently, any special re- 

 lation to the growing 

 point. On the lat- 

 eral margins are then 

 formed two other arche- 

 gonia, not, however, 

 simultaneously ; and 

 finally a fourth may be 

 formed in front : three 

 or four archegonia 

 in all seem to be the 

 ordinary number. The 

 stalk of the receptacle 

 is also a dorsal append- 

 age of the thallus, and 

 not a direct continua- 

 tion of it. 



Fig. i8. — A. Clevea sp. A, longitudinal section of the thallus 

 showing the dorsal origin of the female receptacle ( 9 ) ; v, 

 the growing point (diagram after Leitgeb) ; B, Reboulia 

 hemis/'/uj'rica (KdiAA.), longitudinal section of very young 

 receptacle with the first archegonium ( 9 ) ! -I'l the apical 

 cell, X 300 (after Leitgeb). 



The next type 

 is that which Leitgeb'^ attributes to Grinialdia, Reboulia, 

 Fimbriarta, and some others, but it is not the type found 

 in Fimbriaria Calif ornica. In this type the structure of 

 the receptacle and the origin of the archegonia are the same 

 as in that just described ; but here the growing point of 

 the branch forms the forward margin of the receptacle, 

 and the stalk is a direct continuation of the axis of the 



^ The sporogonial receptacle of the Marchantieje is sometimes known as the 

 CarpocephaUnn. 



- Leitgeb (7), vol. vi. p. 29. ^ Leitgeb, I.e. p. 30. 



