ZEA 169 



were of unusual appearance, being 5 feet high, with short 

 internodes and broad leaves. 



Opening of the Flowers, and Pollination. — Cross-pollina- 

 tion, consequently cross-fertilization, is the rule in com but 

 self-fertilization frequently occurs. Wind and gravity are 

 the chief factors in pollen dissemination, although bees 

 visit the flowers and are evidently concerned in pollen 

 dispersal; they are relatively of far less importance than 

 wind. 



In the case of the staminate inflorescence, the first flowers 

 to open are those near the upper part of the central spike; 

 blooming spreads both upward and downward, more rapidly 

 downward. The same order of blooming occurs on the 

 branches of the tassel. 



The time of pollen shedding depends upon weather con- 

 ditions. Cold, wet, weather retards or even prevents the 

 shedding of pollen. On the other hand, droughty conditions 

 hasten the shedding of pollen, but delay the appearance of 

 silks. Hence it may happen that under these conditions 

 much of the pollen is scattered before the stigmas are pro- 

 truded and receptive, and an incomplete filling of the ear 

 results. On sunshiny days, most of the pollen is shed during 

 the forenoon and, in some instances, late in the afternoon of 

 the same day. Individual tassels usually remain in blossom 

 from four to ten days or even more, depending upon the 

 weather. Furthermore, the anther does not shed all its pollen 

 as soon as it opens, but discharges it a little at a time. In 

 investigating a number (59) of varieties of corn as to the 

 time elapsing between the appearance of anthers and appear- 

 ance of first silks, Gernert finds marked variation. Both 

 dichogamy (maturation of pollen and stigmas at different 

 times) and homogamy (simultaneous maturity of pollen and 

 stigmas) may occur. Furthermore, in dichogamous indi- 



