Durand : Marchantia polymorpha 325 



diagonal walls very distinctly in some of the cells, but not in all, so 

 that they seem to disappear soon after being formed. The nuclear 

 phenomena accompanying the production of the spermatids and 

 their transformation into spermatozoids, together with the changes 

 in the blepharoplast and the development of the cilia have not 

 been specially studied, since they have been so recently worked 

 out by Ikeno (03). 



The writer has not yet observed the explosive discharge of the 

 spermatozoids, which is so easily seen in Conocephahun when the 

 moisture conditions are right. The same phenomenon probably 

 occurs also in Marchantia, and one can easily see how it might be 

 useful in effecting fertilization in those archegonia which are 

 matured after the elongation of the stalk of the gametophore. 



Archegonium 



In the vicinity of Ithaca, the young archegoniophores begin to 

 appear early in May. Archegonia mature and fertilization usually 

 takes place by the time the stalk begins to elongate. The necks 



ot such mature organs are strongly curved outward toward the 

 margin of the receptacle. If the first-formed archegonia are fer- 

 tilized, few are produced subsequently, but if fertilization is not 

 effected they continue to develop in numbers even after the stalk- 

 's somewhat elongated. The necks of the later-formed organs are 

 nearly straight. Fibres 32 to 6p were made from material col- 

 lected when the stalks of the archegoniophores had just begun to 

 ongate, and when mature antheridia were present on adjacent 



plants. 



May 



tlQ n. The sections are 8-10 ft thick and stained in Delafield's 

 hematoxylin. 



e arc hegonia arise in radiating rows from the tissue between 



e lobes on the underside of the gametophore. The youngest 



are near est the stalk and the oldest near the margin. The develop- 



Ma 



' nce lt: differs in some particulars it seems best to give a brief 



account of the whole process. A superficial cell pushes outward 



eyond its fellows and its distal part is cut off by a transverse wall. 



hemispherical cell thus formed is the mother-cell of the arche- 



Ofc* 32, 33, 4 o) 



its deeply 



