1914] Mccormick— symphyogyn a aspera 411 



Again, he says (4, p. 34) in regard to the Ricciaceae: 



As the sporogonium increases in diameter, the central cells begin to separate 

 and round off. Their walls become partially mucilaginous and in microtome 

 sections stain strongly with Bismarck-brown or other reagents that stain 

 mucilaginous membranes. With this disintegration of the division walls 

 the cells separate more and more until they lie free within the cavity of the 

 sporogonium. 



Farmer (io), in discussing Pellia epiphylla, says in regard to the 

 spore mother cell: 



At first more or less irregularly spherical, it soon becomes four-lobed, and 



these lobes increase in size, chiefly owing to radial extension, so that the spore 



mother cell ultimately comes to consist of four large sacs whose cavities 



communicate with each other by means of a small central space common to 

 them all. 



In a later paper (n), in summing up the characteristics of the 

 sporogenous tissue of the Hepaticae, he says: 



A third feature of some interest, and which in practice is especially notice- 

 able, is that just at the period of the spore-formation it becomes exceedingly 

 difficult to fix the cells without some contraction. This is the more remarkable 

 since the nuclei, which may happen to be dividing in either earlier or later stages, 

 present not the slightest difficulty. Moreover, the cytoplasm also stains deeply 

 with most nuclear stains, and everything points to the conclusion that there is 

 something going on in the cell during this so-called reduction division which 

 is not met with at any other period, whether in resting or dividing cells. 



1 



Wilson (34), in regard to Mnium hornum, says: 



Farmer has already noted that at the reduction division the spore mother 

 cells of the Hepaticae can only be fixed with great difficulty. This is especially 

 the case in the Muscineae. 



Of the spore mother cell of Pallavicinia decipiens, Farmer (10) 

 says : 



The mother cell becomes tetrahedrally lobed, and the cell walls at their 

 inner angles grow into the cell cavity towards the nucleus. 



These citations are representative of the literature on spore- 

 formation in the Hepaticae. 



While the spore mother cells of Symphyogyna are comparatively 

 small, the large amount of sporogenous tissue in each sporophyte 

 and the deep lobing of the mother cells make it a favorable species 



