EMBRYOGENESIS IN THE BRYOPHYTA 



65 



Biinning and Wettstein (1953) have shown that the polarised 

 development of the germinating spore in Funaria can be suppressed by 

 various chemical treatments. 



THE DEVELOPMENT OF THE EMBRYO! GENERAL ACCOUNT 



In most bryophytes, the Anthocerotae being an exception, the 

 archegonium is typically free and seated on a short stalk, i.e. it is not 





(fh 



Fig. 13. Liverworts: segmentation of the zygote and development of 



the sporophyte in the three principal groups 



A, Anthocerotales. B, Marchantiales. C, Jungermanniales. I-Ij, the first partition 



wall of the zygote. In the Marchantiales, Meyer distinguishes filamentous and 



quadrant types, the latter being held to be derivative. (After Miiller). 



embedded in the tissue of the gametophyte. The fertilised egg is there- 

 fore unlikely to be affected by compression due to the contiguity of 

 prothallial tissue, (though it might be by the stout venter wall), while 

 effects of gradients, other than those of gaseous concentration, must be 

 exercised by way of the stalk. That metabolic gradients determine or 

 affect the position and formation of the archegonia as well as embryo- 

 genesis seems probable, but the relevant facts have still to be obtained. 



