1 9 14] Mccormick— symphyogyn a asp era 409 



separating the amphithecium from the endothecium. Three wall 

 layers are formed, the middle layer being apparently cut off from 

 the outer layer (fig. 38). The walls of the outermost layer of cells 



matures 



mature 



phyogyn 



numerous 



The beaklike extension of the apex of the capsule is prominent, as 

 Leitgeb noted in the species which he studied (fig. 38). The foot 

 of the mature embryo is often somewhat anchor-shaped, but more 



narrowing 

 l mosslike 



The cells 



of the thallus surrounding the sporophyte become greatly disinte- 

 grated, and the foot of the mature sporophyte is imbedded in a 

 mucilaginous mass. The pad upon which the archegonia stand 

 elongates as the embryo grows, and the non-functioning archegonia 

 are carried up to the apex of the calyptra. Five young embryos 

 were found in one group, and it is quite common to find two or 

 three together. The potentially sporogenous cells are sharply 

 delimited from the beginning by their denser cell contents, larger 

 nuclei, and active cell division. 



SPORE MOTHER CELLS 



The subsequent history of the sporogenous part of the embryo is 

 interesting and important, for there must be a fundamental process 

 which lies back of the formation of the curiously lobed spore 

 mother cell so uniformly characteristic of the Jungermanniales. 

 In the Marchiantiales it is a simple matter to dismiss the formation 

 of the spore mother cells with the familiar expression that they 

 "round up"; but the formation of a lobed mother cell demands 

 more consideration. However, the stages immediately preceding 

 the rounding up of the mother cells in the one group, and the lobing 

 of the mother cells in the other group, are fundamentally the same. 

 These stages in permanent mounts show the sporogenous cells 



irregul 



tie fixation or imbedding. As mentioned 

 admits that he did not understand the m 



