108 



Transactions . 



Archegonia apparently only develop on branches which have already 

 borne antheridia. As is the case in the formation of antheridia, the meri- 



stematic region of the branch 

 is towards the lower surface. 

 The cells of the growing 

 region are distinguished by 

 their large deeply staining 

 nuclei. 



As in other species, the 

 archegonia can each be traced 

 to a single cell which divides 

 into three, the outer giving 

 rise to the neck, the middle 

 to the neck canal cells, and 

 the innermost to the ovum. 

 The nucleus of the ovum 

 stains deeply, and often 

 shows two deeply staining 

 nucleoli. In the central row 

 of cells only two walls ap- 

 parently are formed. In a 

 mature archegonium readv 



Fig. 35. — Longitudinal section of a young 

 antheridial branch, showing initial cell (i) 

 pushed to the lower surface ; an, an- 

 theridum ; rh, rhizoid. x 267. 



for fertilization there appeared a large ovum with a small nucleus close 

 to it, then a large nucleus and three pair of smaller nuclei separated 

 from the ovum bv a wall. 



Fig. 36. — Longitudinal section of foot of young plant of L. Billardieri, showing sus- 

 pensor (susjj). ar, remains of archegonium; /./, limiting layer X 267. 



Fig. 37. — Prothallium of L. Billardieri, bearing young sporophyte, showing only one 

 leaf, I. ft, foot; a, stem; par, paraphysis; veg.br, vegetative branch. 

 X 82. 



