188 



Mycologia 



A great many different stages can be found in the two regions 

 figured. The sorus has about reached its maximum width and 

 very little marginal extension will occur. In the region at the left 

 between a and b the growth of the hyphal mass has not been com- 

 pleted. At b the terminal cell appears to have begun to degen- 

 erate, to judge by the condition of its nuclei. The subterminal 

 cell of this hypha is rather long for a basal cell and no doubt an- 

 other cell will be cut off. From c to d terminal growth has been 

 completed, so that the buffer cells can be recognized ; they have 

 begun to elongate and their nuclei are seen in the early stages of 

 degeneration. In one cell the nuclei are breaking down. At m 

 (below) the nuclei are degenerating without swelling. At o, q 

 and r the degenerating nuclei look like poorly fixed division fig- 

 ures. There is a depression in the pseudoparenchyma at f, as 

 though the cork cell above offered considerable resistance. The 

 basal cells here are at a lower level. Growth certainly was not 

 as vigorous at this point for some reason. At q and r very long 

 buffer cells still persist in a region where spores are being ma- 

 tured. The whole primordium rs*"quite a compact mass of cells 

 wedged up under the cork. 



Stages similar to those shown from d to g in the upper figure 

 were found for a considerable distance along the section. A 

 region in which most of the basal cells have begun to bud out is 

 shown in the lower figure. At h the bud has pushed into the 

 empty terminal cell. The nuclei have not yet begun to divide. At 

 p two adjacent cells have somewhat longer buds and the nuclei 

 are dividing conjugately. At k nuclear division has been com- 

 pleted and the four nuclei appear to lie well up in the tube. This 

 bud is not within the buffer cell but is bent downward so that the 

 septum if formed is not visible. At i there are two buds from 

 the same cell, one of them is growing out between two buffer cells. 

 Several other similar stages can be seen in the figure. The two 

 nuclei are dividing in an older bud in the region near s, where 

 two-celled buds and two-celled spores are also shown. The nuclei 

 in the cells of the larger spore are just fusing. The cork layers 

 above are not yet completely broken open at this point. Un- 

 doubtedly the further elongation of spore stalks will be a factor 

 in completing the rupture. 



