George Raymond Gage 



15 



The most logical way to proceed seemed to be to determine first the 

 fate of the chlamydospores introduced into the blossoms at flowering 

 time, or, rather, the position in or on the seed of the structures of thd 

 pathogene which live over from blossoming time to planting. This was 

 done by a process of elimination. 



Five similar lots of seed (the term seed is used to designate the cary- 

 opsis with its enveloping glumes) from the supply mentioned above, 

 were used. The first was treated with formalin; the second was un- 

 treated; the third was deglumed (the glumes being removed carefully 

 with forceps) ; the fourth was deglumed and then about one-fourth of 

 tlif stigma end of the caryopsis was cut off; and in the fifth, one-fourth 

 of the stigma end of the entire englumed seed was removed. All five 

 lots were sown at the same time, June 10, at the rate of 13 grams to a 

 15-foot row and approximately l 1 /*? inches deep. The results are given 

 in table 1 : 



TABLE 1. Percentage of Smutted Plants Resulting from Different Treat- 

 ments 



Since 2.62 is 39.28 per cent of 6.67 and may be assumed to represent 

 the percentage of total infection due to parts of the pathogene in or on 

 the gl mnes. then the remaining 60.72 per cent must necessarily come 

 from pathogene structures in or on the caryopsis. Regardless of lite na- 

 ture of these parts — that is, whether they are spores or mycelium — the 

 fact Unit they were accountable for 60.72 \>> r c< nt of all infected plants 

 would indicati <il oner I hut mycelium in I he glumes is not I In chief caust 

 of seedling infusion. By subtracting the percentage due to pathogene 

 structures in or on the glumes from the percentage die' to those in or on 

 the glumes and tin' stigma end combined, the amount due to pathogene 

 structures in or on the stigma end alone may he obtained, namely, 11.4 

 per cent. This indicates that those pathogene structures in or on the 



