TI9 



friTn 



formation was seen at once. The inability of the seed covering to free itself 

 entirely from the grain was due to a connected firm, homogeneous, some- 

 what dark mass (Fig. 13) ; the presence of thick, much ramified mycelial 



threads, often provided 

 with short skein-like groups 

 of branches, could be 

 proved. The threads of the 

 colorless, strongly refrac- 

 tive mycelium grew trans- 

 versely through the very 

 thick w^alls (Fig. 13 m) of 

 the fruit cells and seed coat 

 which had been merged into 

 one another. The mycelial 

 threads grew more thickly 

 when the cells were richer 

 in content and thinner wall- 

 ed, entirely filling some cells 

 of the endosperm (Fig. 13 

 mm). 



Near such places the 

 starch had been dissolved 

 and the cytoplasm had be- 

 come solid as if it had been 

 dried. In other cells a firm 

 network of protoplasmic material scarcely distinguishable from starch could 

 be seen. These were almost imperceptible in the starch grain but yet were 

 there. This substance was apparently deposited about the starch grains but 

 upon examination there were no grains 

 present, only the corresponding cavities. 

 In some such way originated the yellow- 

 ish, translucent places between which 

 lay groups of cells especially rich in 

 starch. These mixed regions gave the 

 proper iodine reaction under a weak 

 magnification. 



The variation in the structure of the 

 diseased grain is best shown by compar- 

 ing figures 13 and 14. The latter repre- 

 sents a section from a corresponding 

 part of a healthy gain. The seed coat 



(Fig. 13-14 fs) in the diseased grain is more than three times as thick as in 

 the healthy grain. In the abnormally developed seed coat there is a com- 

 pletely developed vascular bundle with a clearly recognizable sheath (gs). 

 In the diseased grain the growing fruit membrane passes directly over into 



Fig-. 13. Hypertrophied testa traversed by mycelia. 



Fig-. 14. Normal fruit and seed 

 membrane together with the gluti- 

 nous layer. 



